The well trodden and well marked trail begins in the rainforest, and is flat and follows the river for the first few miles. There are many marked camp sites along the way, as well as dispersed camping on the sand bars in the river bed. Follow the trail until the first major intersection, at the Olympus Guard Station at mile 9.1. This would be an awesome place to camp if you have a large group, as it's a fairly wide open meadow; alternately you can hike another mile and a half to Lewis Meadow, which also has a plethora of campsites. 

2.7 miles past Lewis Meadows, you'll cross High Hoh Bridge, you'll hear the water long before you see it. There are a few designated camp sites just past the bridge. 

1.8 miles further there is an emergency shelter as well as a pit toilet at Elk Lake. To reach Blue Glacier, continue another mile further. There will be a split in the trail, to reach the overlook point you'll want to take the left  fork. Prepare for an uphill slog! The last few steps before you crest the hill, you'll start to wonder if you're going the right way or if it was worth it - it is! Suddenly, you're at the overlook point, and Blue Glacier extends massively in every direction. 

Bring lunch and enjoy it while taking in the beauty of Blue Glacier!