i would certainly trust it. a 4.0 inline 6 can hardly be killed. i ve seen some guys with so much blowby that they would have to put oil in it after the trail run, then theyd drive it home. as long as its not burning major oil, i would just change the fluids incl. oil and filter, tranny, transfer case, and differentials front and rear; do a tune up(which it sounds like youve done) and give it a good greasing, such as the steering and balljoints and check the drive lines to make sure they dont have any grease zirts, as well as check for looseness, if that thing wobbles around really bad it means you may need new u-joints(always a good thing to take on the trail with you anyway) As far as duribility, Jeep is the best, in my book. ive seen stock or slightly modified jeeps do amazing things. SMORR is probably the BEST place to go wheeling even by yourself. it is centralized where every trail ends at or very close to a central logging road(check out the map), if you break, its less than a mile walk back to the truck. The cleanup would be a great thing for you to go on cause it will let you get to know the guys who know SMORR best, cause most of those who help clean are the ones who helped build it. welcome to jeeps and you may want to take your Jeep Flu shot or youll be offroad crazy like to rest of us.
Hope to see you on the trails!!
Ryan