Here is an excellent thread to read:
How big of a tire can I fit on my truck
with that said, there are quite a few people running 35s with a 3" lift. i do not, so i don't have any personal experience to share. however, from what i have read, if you plan to offroad, then you will more than likely run into contact issues. you will probably need to drop your bump stops, change your gear ratios, and must chop your front body mounts.
