I think it depends a lot on where you are located. For example I see a lot of high mileage Jeeps from down 'south' that are probably just great. Up here in Canada where we have as much salt on our roads as McD's fries I would be wary because of the amount of rot that occurs.
For example the 90 Explorer I just got rid of had 200,000 miles on it and mechanically it was fine. The body was disintigrating. My 86 CJ with 2 winters on it is in much better shape because it got very little winter driving.
Maintenence is also important. You could buy a low mile Jeep with poor service record (eg oil not regularly changed) vs a higher mileage Jeep that the owner fixed each time they noticed something going wrong.
Don't be in a hurry to buy something, that's when you will make a mistake. You'll know when you find the right Jeep....
First off, you need to specify what "Jeep" you are looking at. An XJ with 100,000+ miles that is a 98+ will go for a pretty good price. Most I see on craigslist here, which is cheaper than resale, are still in the 5-6,000 range. Im not sure on the other Jeeps because I am most knowledgeable in the XJ field.
When dealing with high miles on a 4.0 HO engine, you must understand how long they run. I just recently sold a 96 XJ with 219,000 miles for $3000. Not only is it easy and cheap to swap engines, the 4.0 will last almost forever if taken care of properly. Now some may argue that any engine will, but I dont believe that to be true, or to the extent that other engines will run as well as the 4.0.
[B]'95 XJ[/B]-Hunter Green
3.5" RE Superflex with OME shocks, 31" (movin up to 32")Mud Country on Soft 8's
Jeeps are probably the only american car you can be over 100k and not even give it a second thought. It won't run like brand new, but with the inline 6 you can get 200k easily if its been taken care of. I ran my old XJ from 35,000 miles to 185,000 miles and never had a problem.