Not to belabor the detailed info provided in prior trip reports, but some key takeaways from our experience:

-If you don't arrive at the parking lot trailhead in the early AM or late afternoon, expect to wait in a long caravan of cars at the park fee tollbooth. Once the parking lot is full, the park rangers only allow new cars to enter after the same number of cars have exited. We waited over an hour to enter. We only had a short first day, so fortunately we weren't too sidetracked by the delay. Would definitely factor this into future trips though, and either arrive early/late, or just plan a shorter mileage first day.

-Flush toilets available (luxury!) at the trailhead at the visitor's center, along with a refillable water station.

-Trail was more popular than I anticipated. I expected the day hikers along the first section of the trail, but I encountered plenty of backpackers/climbers throughout the trail. Definitely did not expect to show up to campsites at 4:30pm to be greeted with a dearth of camping site choices, basically just the leftover dregs at that point.

-Bugs surprisingly not that bad for this time of year. Not sure if it was because of the trail mostly avoiding lakes, but this counted as a welcome respite.

-The humidity and lower beginning elevation translated into a warmer backpacking experience than I was used to. The humidity especially made the temperature feel warmer than it actually was. On hot days 80F-90F in the valley, this made for a sweaty ascent, despite the mostly shaded trail. Saw plenty of backpacking parties parked bedside the river/creeks for a brief cooler respite near the water. However, don't discount the weather changes at higher elevations near the glacier. It started drizzling on and off during our final push to the glacier, hammering home the point that this is rainforest territory. This was also a good reminder not to rely too heavily on weather forecasts, which didn't predict any significant rain on that day. The brief rain probably would have been unwelcome in cooler weather, but it was still hot enough that the damp clothing and cool wind only translated into a more pleasant uphill slog.

-Trail washout requiring ladders and a rope is well-detailed in prior trip reports. I used glovers which made the experience less harrowing. Otherwise trail in great condition, no blowdowns or mud to speak of, all creek crossings manageable without wet feet.

-Split up the trip into 3 nights, which worked out well, especially factoring in the long wait at the national park entrance which delayed our start.

Day 1: Hoh River TH -> Happy Four camp ~5.7mi
Shorter mileage first day in the heat, camped on the gravel bar and woke up to deer meandering through the camp
Day 2: Happy Four camp -> Martin Creek camp ~9.1mi
Split up the total elevation gain into two days, this being the first section. Camped at a secluded site away from the main drag, since the majority of sites clustered together without much privacy. No backcountry privy available here
Day 3: day trip Martin Creek camp -> Blue glacier -> backtracked to Martin Creek and donned packs down to Lewis Meadow ~11mi
Happy to carry only daypacks for the final ascent up to the glacier, especially for the final slow-going slog through a talus field. Spent time on both the Lateral and Terminal Morraine trails, and definitely the Lateral Moraine trail was the showstopper with dramatic views of the glacier backdropped by Mt Olympus.
Day 4: Lewis Meadow -> Hoh River TH ~10.5mi
Easy flat cruising, got an early start and didn't see anyone until Five Mile Island

Couldn't snag permits for Enchanted Valley or other popular places, so a quick trek down the Hoh it is!

We arrived Saturday night and slept in the car to beat the morning line on Sunday -- wait times can quickly add up once the lot is full. A quick nap in the lot, and we woke up to see rangers shooing a elk and her calf away from the parked cars. After a hearty breakfast and a late start, we strolled past the dayhikers, often scattered towards Mt Tom Creek, and for the energetic, towards Five Mile Island. 

The Hoh River Trail during the summer is a parched, maple-shaded stretch that feels like a riverside park in Puget Sound than a rainforest (totally different in the wet season though)! Raspberries and trailing blackberries sprout from the sunny patches, like between Five Mile Island and Happy Four. Up to Olympus Guard Station, you can camp on the gravel bars, though the banks are primarily rocky. All the camps have flagpole-style bear wires, though some (like Martin Creek) were especially ineffective, and hooks are limited. There's also a logjam detour after Happy Four over a creek, but fairly easy to navigate.

I didn't prefer the mosquito-heavy meadow camps, and continued past Lewis Meadow, where the trail finally starts to ascend into the more-convincing subalpine forest. We stopped at the signed camp at 12.4 Mile, along a thundering stretch of the Hoh, where we had the place to ourselves. Additional marked camps at 13.1, 13.2, and 13.3 are first-come, first-served, with bear canisters a necessity. 

The next morning we hauled up the slope, refilling water at refreshing Martin Creek. Elk Lake, just around the corner, is home to well-distanced sites, and the last chance to ditch your tent if you don't want to haul it up the sketchy rope ladder, which emerges after your first glimpse of Olympus.

When we arrived at the rope, a bottleneck of six folks were waiting to go down, with three folks coming back. The ladder isn't bolted, so folks opted to rappel down the side of it (slide one hand down, grab with the other, repeat). A kind trail angel left a couple pairs of gloves to borrow, but the rope didn't cause too much rope burn. The slope continues to erode under each person, and we saw a large boulder tumble down, with one climber having to quickly dodge it. Make sure your shoulder straps are secured close to your back!

Glacier Meadows camp is right after the ladder, with the first cluster tightly packed. One camp is distanced away from the rest, which you can find on the posted camp map. Up the hill is the literal foundation of a guard station, with the actual building absent. 

Continue to a fork for the terminal moraine (bottom of the glacier) or lateral moraine (climbing a ridge aside the glacier). I opted for the latter, which takes you up another 1000' in half a mile past colorful wildflowers, with a stunning view of Olympus as you emerge at the top. I worked my way down a steep primitive bootpath, careful of the sliding rocks. The glacial ice is beautiful underneath, with the covering snow having melted off at outer reaches. Tracks in the snow showed mountaineers destined up Mt Olympus. There's only a few small trickles of water, so fill up at the meltwater pond before the final climb.

I hauled back to Glacier Meadows as the sun crested over the horizon, bundling up for the chilly night to come. The next morning, we bolted down the slope, up the sketchy ladder, and stepped aside as four groups of mountaineers trudged up with their ice axes and helmets. 18 miles later, we pushed through the throngs of families and emerged exhausted into the packed parking lot. 

If you snag Seven Lakes permits, a through hike from Hoh to Sol Duc can with a detour to Blue Glacier. Just keep the 27 switchbacks up to Hoh Lake in mind though!

3d/2n backpack

permits: need reservations for backpacking sites and Annual Pass or Olympic NP pass to park 

road: most paved with road work along several sections (we drove in on a Monday morning and wait probably ~45 min in total), at the entrance gate we waited ~30 min (driving out Wednesday early afternoon it appeared the wait was at least several hours) 

TH --> Lewis Meadows (~10 miles): generally flat hike through the rain forest along the Hoh River. Easy and pretty (although monotonous) with a nice stopping point at 5 mile campground. Lewis Meadows had many spots to camp (meadow and along the river bank). We were along the river bank with a breeze and did not have any problem with bugs. We saw a bear (and her cubs) several miles in ~10 feet from the trail. 

Lewis Meadows-->Blue Glacier and back (~16 miles RT): this was a manageable although long day hike. The first several miles are flat and then the elevation starts which is pretty unrelenting (again challenging but entirely doable with a daypack). The washout before Glacier Meadows was larger than I expected and the ladder/rope were doable although the numerous missing rungs, scree, and tree that it is attached to made me uncomfortable. I was glad to have gloves to wear to grip the rope/cables, and I was glad to only have a day pack on this section. The mosquitos were buzzing as we hiked through Elk Lake and Glacier Meadows sections and hikers who spent the night there confirmed that the bugs were an annoyance. The glacier was spectacular (we hiked up to the terminal moraine for the view and saw a group traversing the glacier. 

Lewis Meadows -->TH (~10 miles): again easy, but long, generally flat hike out. Expectedly very crowded in the area around the trail head. We saw a herd of elk just off the trail. 

We had no issues with stream crossing (all easy to navigate). 

To the green team we hope you had a great trip! <3 the red team 

Had a wonderful 4-day/3-night hike of the Hoh River trail up to Blue Glacier.

Summary Notes:

• It took about an hour to get through the gatehouse at the park entrance in the early afternoon on a Saturday. It looked even busier on our way out on a Tuesday afternoon. Plan accordingly.
• Most of the trail is easy walking, but there are still plenty of expected obstacles like mud & water, downed trees, bridgeless stream crossings, loose rocky trails, and narrow spots with steep drop-offs. The difficulty ramps up the further up the river you go. If you're looking to backpack this trail this shouldn't be of any surprise.
• The trail washout and rope ladder prior to Glacier Meadows is major, and requires some rappel-like maneuvering. Some gloves are nice to have.
• Water access is generally easy and plentiful, but as noted below there is no immediate water access at Elk Lake campsite, despite the name.
• Mosquitos were definitely out, so bring long sleeves and bug spray particularly for camping. Not bad while moving, but they find you when sitting still. Overall not terrible but certainly got a few bites.

Day 1 - TH to Olympus Guard Station (~9 mi): Not too much to say, this is the easiest stretch of trail. Mostly flat and a lot of day-hikers in the first few miles. Kept up a fast pace and had a great campsite right on the river's edge at OGS.

Day 2 - OGS to Elk Lake (~6 mi): Past Lewis Meadow the trail starts to climb, gaining something like 2000 ft in a few miles. Not outrageously steep but with overnight packs we felt it. I was slightly surprised to find that there is effectively no lake access at Elk Lake. Camp sites are nice enough but the water access is about a quarter-mile back down the trail at Martin Creek.

Day 3 - Elk Lake to Blue Glacier, then back to Lewis Meadow (~11 mi): The big day with the big pay off! Left our overnight packs at Elk Lake and ascended the next 2000 ft up to Blue Glacier less weighed down. As noted by ONP, there is a major washout of the trail about half a mile or so before reaching the Glacier Meadows campsite. The rope ladder at first glance looks gnarlier than it is, but it's not trivial so be aware. Past Glacier Meadows campsite, the trail becomes truly spectacular as the tree cover gives way to alpine meadows and views of Mt Olympus and the surrounding peaks. It remains steep all the way to the ridge overlooking Blue Glacier. Some small amounts of snow still remain near the very top, but it's almost not worth mentioning if you've come this far. The views are spectacular once reaching the glacier. After taking it all in and refueling our bellies, we descended back down, picked up our packs, took a break at Martin Creek, then made our way down to Lewis Meadow for the night. We scored a lovely secluded campsite next to the riverbed for the final night, though the actual river was a short walk to access.

Day 4 - Lewis Meadows to TH (~11 mi): Powered out the mostly-flat return stretch with a brief lunch stop at 5-mile island. Not much to report, it's a cruiser stretch back to the TH just a long one.

All in all it was a great trip and I recommend it!

Don't underestimate the terrain from Elk Lake upwards. It was the most beautiful part, IMO, but I imagined a chill-er low-mileage day by camping at Elk Lake and then at Glacier Meadows (hiking from lake to glacier, then sleep at GM camp, then descend) but it was still definitely an all-day affair for an average/low?-fitness, young adult novice who started any of this hiking stuff in April. I developed a shin/knee injury during my 'summit' day which made descent difficult, resulting in a three hour traverse from Glacier Meadows to Elk Lake on the first bit of my descent hike the following morning.

I planned my overnights such: Happy Four (1/3 bear wires are functional), Elk Lake, Glacier Meadows, Olympic Ranger Station

It was strenuous for me, but I am very happy with how I spread out my campsite choices, especially considering how long the GM->EL segment took me.

There is a tragic amount of damage from the heat wave. Sections of the forest at low elevation are heavily perfumed with dead vanilla leaf.

I explored both moraine views and I preferred the terminal moraine. The lateral one is more hyped I think, but if the WTA picture sold you, that view is from the Terminal Moraine where there are some really cool rocks.

If you can only do one:
Lateral moraine has a more complete view of the bowl the glacier sits in including Mt Olympus. Bowl felt half empty.

Terminal moraine felt like I was more up close and personal with the monster itself. Bowl felt half full.

So- mountains or glacier?