Evan's is about 3000' at the staging area and tops out at about 5200'. There's definately snow up there. A group of us were up there last Sat. The trails were slick. Your JK should be fine. I'm not sure about 31's. Maybe a little extra throttle?
6" FT LA, 315/75R16 MT/R's, AntiRock, FT Rear sway, Rockhard rear bumper/tire carrier w/frame kit, some other trinkets.