A full day float will be kind of difficult, its only about an hour to Rainie from the launch at Graves creek. There is a nice little campsite just after Graves creek falls on the left. But you just packed your boat to row 10 minutes down river.
You want to be on river left to hike the falls, the campsites just aren't that great above the falls on that side. You could camp below the falls about 2-3 minutes float on the left and walk up. There is a little hideout cove to camp in.
Here is about what I do I use the names for general reference because I have alot of my own unnamed camps I do.
Night 1. Tyee -ish
Night 2. Kelsey Canyon- ish
Night 3. Night 3 above the Ranch somewhere
Night 4. Below Tacoma somewhere take out in 2 hours
All subject to change on the fly,
Here is one of my last spots just above zane cabin,it is an island