your best bet, is do what i did, find a somewhat rough (IE some rust, dents, bad paint yadda yadda) ex military truck, known as a CUCV, youll want the M1009 version. they are very simple, no frills, and easy to work on. i got mine from a farm boy down in charlottesville VA for 1500 bucks. and it was in running shape when i got it... now, ive had to sink money into it, mostly to fix the stuff the farmboy goobered. alot of stuff on this truck hadnt been serviced for a longgggg time.
as of this point ive probly put 5000 into it, but i have put a new starter, new glow plugs, rebuilt both alternators, rebuilt both front hubs and brakes, bought (but have yet to install) the parts for the rear brakes, air cleaners, fuel filters, diesel fuel treatment, oil change, oil fitler, replaced the U-joints (it spat out the rear driveshaft). its broken down a time or two, but its always easy to fix.
i drive it as a daily driver, going to and from work, alot of stop and go, i get around 17 mpg around town, probly 22 or so on the highway. the military trucks came with a three speed TH400 tranny, which is bulletproof, but sucks alot of power from the drivetrain, and gives up some fuel mileage with bad gear spacing, and no overdrive, but the axles are highway friendly with 3.08 gears. not the best around town, especially with big tires, but not bad on the road, i can cruise very comforateably at 55-65mph.
as for off road, with the stock suspension, and 33in goodyear wrangler MT/R's you wont be taking on any serious rock trails, but i hit up the GW national forest, which is alot of trails, water, mud, and a few pretty challenging parts for beginning off roaders, and there wasnt anything there it couldnt handle in 4lo. (except some boulder trails that i didnt have the ground clearance for). and there were only two times when i had to take it out of 4hi to get up and over some steep sections.
i have no regrets buying this truck by any stretch of the imagination. in fact were using it to haul all the camping gear for me and ten of my friends in july. and im taking another friend campin and four wheelin. and still drivin it every day. the only thing i am looking to buy at this point is a new harmonic balancer.
future plans are a 4in lift, 35in tires, 3.73 gears, detroit lockers front and rear, and a turbo. and wish list, would be a built 700R4, and NP203 transfer case.
most people talk about how gutless the 6.2 is but its just fine by my standards for a full size truck, i have no problem accelerating up to highway speeds. i certainly wouldnt drag race anyone in it, but for regular driving i dont think youd be dissapointed. the civilian version would have the 700R4, which would be very nice for the deeper first gear, and overdrive on the highway, and would have far more creature comforts. but would probly cost a bit more.