I have a friend with a compressor... he might have a grinder too. Any specific grit?

 

flapper disc would work, I know they make one just for removing rust but you have to be carefull not to eat thru the metal.

you can pick up a sand blasting gun at harbor frieght for $15 and a bag of sand and be done quick, alittle messy if your doing it inside your jeep

 

Just get a cheap Maaco paint job. It will be less than a grand. The quality isn't as good as factory but it will still look nice and you won't have anymore rust spots.

 

Thanks for posting my pics for me Razor, you saved me the time. Anyway, mine is an east coast car as well so there is some undercarriage rust. There was a few parts on the lower doors, but he basically used some sort of anit-rust compound and and then sanded over and re-primed and repainted. Nothing can really stop rust, but it does slow it down considerably. Moving away from the east coast helped as well.

If you paint over rust without treating it (which Maaco won't do) it will inevitable bubble and continue flaking off. I'm planning on keep my Cherokee as long as I can, so I went the high end route. Hope this helps.