I took my entire CJ down to bare metal between 2008-2010 using wire wheels, flap discs, medial blasting and some secret voodoo chit an old man told me about.
Coated everything with SPI epoxy primer and most everything was stored inside my house.
Followed it up with 2K primer, Evercoat filler and finished with PPG DBC base and SPI Universal Clear.
All mainstream good work procedures as far as I know.
Both front fenders have rust returning and I had access to *both* sides of the fenders. I was not surprised to see a rust bubble on the windshield frame and the rear of the tub below the tailgate where I did not have access to the back side of the metal. The fenders on the other hand should not have rust returning this soon. I have thought about this for a few years and want to take additional steps to prevent this on the Cherokee.
Based on what I have read, I believe I should have used a rust converter on the metal prior to priming.
Further, I think it would be important to coat the back side of the metal wherever possible, the A-pillars on the Cherokee are a major concern for me. I am planning to load a rust converter in a chemical sprayer, the air pressurized insecticide/herbicide type and spray the inaccessible spaces. In the A-pillars, I may have to swap the wand tip to a hose and feed it into the pillar but I will make sure that converter is running out and puddling on the floor or the ground before I call it good.