You won't be allowed to camp at Illilouette Falls because of restrictions. You leave GP and head down and you're not stopping until you get to LYV to be legal. Note on this link where the colored lines and arrowheads are.
https://www.nps.gov/yose/planyourvisit/ ... lheads.pdfYou'll have to head upstream a couple miles from GP to camp legally...beyond the points. Unless you want to go up to the Mono Meadow/Buena Vista junction, your only choice down to LYV is the Panorama Trail. I know you saw my post and the wilderness conditions report, so stay apprised of the condition of crossings and meadows.
You know, if you come out of Tuolumne and Soda Springs on the trail to Glen Aulin, you can swing cross country to the north when you come to the first bridge and get to the camp that way. With all the melt and raging water, if you can get past flooding at Glen Aulin proper (and the trail is open at least that far), the falls complex below that ought to be one of the most amazing displays of water you've ever seen. You won't have to even worry about going beyond Return Creek, and there's a lot of great campsites down by Waterwheel Falls that should be just fine.
btw- GP to LYV is decidedly front country...