I, along with a few others, am running 34s (285/75x17) and have A LOT of added weight, especially with the tent on. . I currently am running stock gears and honestly can say I NEED to regear. My truck is constantly hunting for a gear and is sluggish. Luckily I don't daily drive mine so I will put up with it till I can regear. If you are to do your gears you might as well throw lockers in too.
I think 35s are going to be very tight in our trucks, as they are with the previous gens. Can it be done? Sure, but be prepared for the work and to get them to work in the dirt.