i did this to mine about 4 years ago. it was during a build, so i had lots of time till the axles were ready.
i spent many hours sanding and feather edging all the deep scratches and used some spot puddy for the rougher areas before the first coat. there were no holes or rust, so it made it a bit easier.

i used the roller for the most part, but needed a few cans of spray to get in all the nooks and crannies, especially under the door handles and around the mirrors, etc.

then wet sand and add another coat. did about 6 coats, no clear.

it is still holding up very well, albeit a bunch of tree striping. but that just adds character.

oh, and it cost me more than 75 bux, but i had to purchase everything from sand paper to blocks, trays, rollers, primer, tape, tac cloths...

 

I was thinking about doing flat olive drab like the army trucks before my mom said she'd have my jeep repainted. I still think it would look BadA** if someone did it to an XJ.