Other than the 44 front being a bit weak for those tires, that looks like a pretty good rig. Motor, t-case, and tranny are all great equipment. For what you want it for, it sounds like if you wanted to, you could sell those tires and maybe even the overdone lift and end up money ahead with a bit more managably-sized wheeler. The steering is probably stock since he didn't mention crossover, which may or may not suit your needs. GM trucks had a pretty poor system for off-road use, but you could change that to a crossover system pretty economically if you are comfortable doing work yourself. The welded rear shouldn't deter you much. It isn't that noticeable unless you're on really icy roads or small parking lots all the time. It's not a DD anyways, and it makes a world of difference on the trail. And if you absolutely hate it, 14 bolt carriers are a dime a dozen anyways.
If you go look at it, other than tranny shifting, engine running, etc...look for these things:
Frame damage at the steering box. Have someone turns the tires back and forth while you watch the frame from inside the engine compartment and under the truck, it will flex, but make sure there are no cracks. He may already have a brace on there, if he does, that's a good sign he was building that truck the smart way.
Rear passenger side shock mount cracking the frame. This was a crappy design. If it's cracked there, it's easy to fix with a welder.
Engine crossmember and motor mounts. The crossmembers here sucked and frequently are cracked near all the angle changes. I'd recommend replacing it with an aftermarket one even if the OEM one is OK, but this is a good indicator of the TLC the seller was putting into the truck. It's also an area that you might be able to use to talk him down on price if he's neglected it.
If the thing is in reasonable mechanical condition, you could probably damn-near part it out and make money, so I'd say it looks like a good deal. It looks like a good base for whatever you want for the price. It's a good leg-up on a full-blown 1-ton trail rig, and if you just want a camping rig on 35"s, you could sell off the stuff you don't need and put that money into maintenance and camping gear. I'd probably sell my truck for about that much, and it looks a whole lot worse than that one!
They are a money sucking pit
He's right. A 30+ year old truck is either going to be a $10,000+ collector's item, or a lot of work. But personally, I'd rather build up an old beater by hand than spend $30,000+ on a new Jeep that I don't want to scratch. My friend's refer to mine as "the hole in the ground to throw money in". But hey, I've got less than $3k into my rig, and I keep up just fine with friends that have brand new jeeps on 37s, beadlocks, air lockers, etc...And if I get tired, I can inflate my air mattress in the back and go to sleep
