CA Jeeps shouldn't have rust problems like back east. Look for Jeeps that haven't been heavily modified. If they have been modified rather hearing about all parts and name brands does it look professionally installed and do all the mods match.
Look underneath take some coveralls if need be. Take a rag look for leaks, rubbing on the front end driveshaft and exhaust pipe. Clearance at the diff cover up front. Unusual tire wear.
Drive it and check all the options and all the gauges and the 4X4 it should shift like butter.
Steering should be tight and at full turn no tire rub. Look in the wheel wells for evidence of rubbing.
Interior pull the carpet up look at the floor pans.
And then all the stuff you would look at in a car lot.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184