Rattlesnake Mountain trail is a great option for getting some miles and vertical in on a good quality trail, without all the crowds. You can choose to through hike to the Ledge side, hit the Middle or East peaks, or stop at Grand Prospect for views of Si, which is what we did. Warning: mid week seems to be an old person's trail :) We fit right in. 

Trail is good quality, not too rocky. It cross several roads and some of the mountain biking trails, but signage is clear. Parked at the Rattlesnake Mountain Trail Parking Lot, 2 toilets, plenty of spaces. Lots of mountain bikers in and around this area. First part of the trail is shared so be careful, but after that it separates. 

Stats: 8.4 miles, 2170' gain, 3:15 total time, 0:08 stop time (no time to rest!)

Even though it was a sunny day it managed to still be foggy here in the morning! That was ok, I was out to get some exercise close to home and this was perfect (and it did clear up as I was getting back to the parking lot).

The snow is gone and the bugs are out, I didn't think they were too bad but I was wearing long pants, sleeves and a hat.

Trail is in good condition and was not crowded this morning!

Quite a few trillium were the highlight of the hike for me. 

Arrived around 530p, ran to Grand Prospect as an out and back in about 90ish min.

There was maybe one spot with a very small tree down across the trail. Trail was in MINT condition. A nice runable grade if you're into it!

Plenty of parking even arriving the same time a ton of mountain bikers arrived. Great trailhead vibes, everyone was super friendly.

Decent hike but nothing special. Picked it because it was the right distance/elevation/location but wouldn't recommend as a must-see. Trail in wonderful condition. Through a brushy/foresty area for the first ~1.5 miles and then in some more stately second-growth forest for the remainder. Not many viewpoints along the way. We didn't find Stan's Overlook on our way up - seemed like you maybe needed to follow a mountain bike trail to find it? The view of North Bend and Mount Si at the top was nice. Hiked with my parents (both 60 years old) and we made it to the top in 2 hours and took another 2 hours down after a lunch break at the top.

When we hiked to Grand Prospect there were DNR signs that a number of trails on Rattlesnake Mountain will be closed for timber harvest starting next Monday May 16th until further notice. The map is not clear how this affects the Rattlesnake Mtn Trail and access Stan's overlook or Grand Prospect during the harvest. I didn't find information on the DNR website. If you enjoy this trail get out there this weekend. The previous 2 trip reports are accurate. Patches of snow might be on the trail past Grand Prospect. Flowers- trillium, bleeding heart, salmon berry.