This was a decent backpacking trek. We (2 of us) did it in 3 days 2 nights. We went the 10.5 miles to Lewis Meadows, where we stayed both nights. We did the remaining 17 miles to the base of Olympus and back to camp on the middle day.

Trail was well defined and basically snow free except near glacier meadows and the glacier/Mount Olympus itself. There are some fallen trees on the trail that you will need to go over/under (usually without much difficulty).

To cross water deeper than an inch or two, there are usually bridges; a combination of built ones and log bridges. The log bridges are generally in good condition and a superior choice to wading through the water. One exception might be the log bridge right before you get to the Olympic guard station; It was a somewhat narrow tree that, while solid, made me want to cross slowly and carefully (no one who used it fell, but other log bridges I would have almost felt comfortable running across compared to this one).

As for the snow, we did fine with micro-spikes. The snow was pretty melted out underneath, so I would imagine it might be riskier in another week or two. It was fine for walking and glacading on this trip though. There is a ladder and a rope laid out at one point before getting to glacier meadows that it would be wise to use.

There are many water sources. If you bring a filter (DO bring a filter), you might only need to carry 1 or 2 liters at a time. We carried 3L and passed many creeks/rivers without refilling. 

While camping, there were only minor annoyances (neighbors, bugs, very light rain on the last night - in that order). Camped next to the river, it was relatively pleasant. Didn't use bug spray, didn't regret it too much. Maybe should have used sunscreen, only really needed it near the glacier.

Bear cannisters are a great idea if you don't want to fight for space on the bear wires, although we didn't see any bears. There were some not very shy deer grazing in the meadow near the camp site that we saw several times.

Since it was a holiday weekend, things were pretty crowded. We wanted to camp closer to the glacier, but all the spots past Lewis Meadows were taken (as we were informed when checking in at the visitors center). Would recommend planning ahead, showing up early, etc.

I have one final recommendation: since most of the trail is a (relatively) flat walk through mossy forest next to a river, and the real views don't show up until about 15 miles in (nothing against the forest walk), consider doing what it takes to extend your trip to include climbing Olympus. Now that I've gone to the base to see it, and endured almost 40 miles of walking, I would have gladly gotten training, gear, and added a day or two to the trip to include a climb up Olympus. The glacier view is _majestic_ and many others there like me agreed that we might want to come back to climb Olympus.

The trail is in good condition overall with a handful of minor to moderate blowdowns and obstacles.  Snow-free to Elk Lake.  There are two snow fields, each 50-75 yards long, between Elk Lake and the rope ladder.  They are easy to navigate along the boot path and require no gear, but the snow is melting fast, and snow bridges are increasingly unstable.  Past the rope ladder and just before Glacier Meadows, the snow begins in earnest.  I recommend traction and poles for this section.  The snow is still several feet deep from Glacier Meadows up to the moraine overlook.  There are some narrow snow bridges that require caution along the boot path(s) leading from Glacier Meadows up to the moraine overlook.  There is still avalanche risk for the final half mile.  The glacier was covered in snow, but the view of Olympus from the overlook is always incredible.