Hey Buzz - I checked out the area above rainbow pool/ buck meadows. When my wife & I got there there were kids in the parking lot getting busted for beer & pot - not a great sign

. I hiked up the river - it was pretty high - no pun intended - & pretty much each decent spot contained a family or some inebriated teens/twenty somethings swimming - it did look like a really good stretch though - I'll just avoid it and Yosemite for Memorial Day weekend & try it on an off weekend. No fish to hand but I met a guy who said he caught a couple one above & one below the falls.
I did also try Big Creek past Fish Camp near Wawona & managed a few small ones - the fish are super spooky at least where I was fishing - it was super clear/ spring creek action where everything had to be perfect/ the fly line floating in their line of sight spooked them so I could only show them the leader.
We bought a year pass to the park though so looking forward to the Merced in Little Yoesmite Valley.