things to look for. the rear hatch dosent work on like any Grand cherokee, test it.
Rust, check the entire underside, they love to rust.
Hub bearings love to be worn out in the front, make sure the front dif is good. Drive it on thier lawn and engage the 4x4 and do some turning, listen for the clicks of the front ujoints, they are also common to be junk on jeep. Cheap to fix, if you can get the damn bolts out, but still a headache.
if it has the I6 dont be alarmed by the temp gauge. Ideal running temp for them is 210º
Dont take thier word for it, check it yourself. Wear dirty shit, be prepared to crawl around on the ground, I reccomend eye protection aswell, shit loves to only fall out from under it while your looking up at something.
Check the axel seals, check the driveshaft yolks, then the basics, look for oil leaks, smell for gas leaks, if they let you test drive it, jump on the brakes hard, gives you a good test of the lines.
Alot of this is basic stuff, that is sometimes over looked.
On the I6 its common for the valve cover gasket to be bad, make sure the CCV system is hooked up, its 2 black ports in the top of the valve cover with black hose running between them, its crucial to the long life of the engine.
Let it fully warm up, my old jeep would get 60psi when it was cold, and 0 psi when it was hot, oil pressure.
If I think of anything else, I’ll post it.
Jeepforum.com has alot of info on these too.