The frames do not rot on those Jeeps, bent frames yes, but the are an open channel.
Rotted body's are the death of them, the one Fred posed is a 46 - 48 A.
Engine wise they are all about dead at 20,000 miles.
Fresh re-bore and run them some more.
If it wiil drive and stop $4k is a fair price.
Pay attention if the trans is good, but they are easy to rebuild.