The biggest problem I see with rusty Jeeps is the CJ's and Wranglers have a box frame, road salt and dirt gets in then rust starts.
Friend at work bought a new 85 CJ, in ten years the motor and body was falling apart, the way he fix it was buy a new 97 Cherokee, so far he has around 20k mi on it, 5 years ago had a 8k rust fix job done and on his 4th set of weather cracked tires.........