It's a 3 night backpacking. We camped at Glacier Meadow for 2 nights - it has a quota. I have reserved the campsite a month ahead. To get here, hike 17.5 miles from Hoh River Visitor Center. The first ~12.5 miles are flat. Then about 4000' gain. Some log crossing. Not much view to speak of, other than mossy trees. Glacier Meadow camp has no view of glacier nor meadow. There're 2 emergency shelters, and 2 bear wire stations, about 17 camp sites (2 group sites).
Mosquito is an annoyance. But not too bad.
The high light is going from Glacier Meadow to Snow Dome. We started too late, otherwise, may be able to reach Mount Olympus or at least the saddle below.
There's a hazardous slide area before you reach Glacier Meadow camp. There's a rope to assist you.
Going down and up the lateral moraine at the end of the trail is also hazardous. Loose rock, steep slope. So a good turn around point is at the ridge on the lateral moraine at the end of the Blue Glacier trail, about 1.2 miles (600' gain) from Glacier Meadow camp.