Re: Jeep bought from non jeep dealer
If possible go with a Mopar care contract.
The dealership should have available a GM backed one, and if they are like Ford dealers with their used warranties, they just have a trusted jeep dealer do anything complicated anyway--but the Mopar one gets you a hard copy to keep with you plus is attached to your VIN so any jeep dealer can pull it up.
The Jeep dealer should be able to give that thing a pretty good pre-purchase checkout for you for a modest fee, and should be willing to tell you how much it will cost to fix any important stuff, unimportant stuff, or even minor trim and cosmetic issues.
The fancy gewgaws on that thing are quite expensive to deal with, e.g. auto heat/ac, and tend to cause more cost than basic drive train as long as the 4wd components are in good shape.