I'll echo all of the previous comments, Esp. PeteCz but also comment that the WATER TEMP is more important than the air. I'd still stay "lower" and fish just above Elkmont, I like the water up higher but its still spring. Start out nymphing in Mornings and watch for bugs on the water. I was there two weeks ago, even with QG's on top, the trout wanted a QG wet fly (emerger).
Wet wading is a personal perference. I used to more but found my feet ache and I get clumsy if not careful. Definitely wear felt soles!!
Watch out for snakes- they are there even though you probably won't see them! As far as carrying a weapon, I defer to bear spray. I had a ranger in Wyoming tell it works on Buffalo, Moose, People and Bear. I've had two incidents with being approached by bear up there, neither one required using spray.
Tight line and enjoy