A bit late for Memorial day ! but I've visited twice this year.
June 25 road was clear but Buckeye creek was running quite high due to snow melt.
Buckeye HS was was cold and not really useable. Travertine was fine.
Looked like the creek would remain high for a month.
So go before or 2 months after snowmelt starts.

About Oct 30 Buckeye was in best shape I've ever seen it .
Main pool was 106F (room for about 8). Mostly clothed but some nude use.
mid pool was 102F (room for 3 or so)
next pool down 100F (room for 2)

upper pool by tree with black silt 102-105F
2nd upper pool nearby (for 2 or 3) clear and about 104F

Big news, it's about time, Is the trail has been reworked so it's not a death defying
straight down a steep hill trek. It zig-zags back and forth to allow much easier access !