you don't need to go down to the bare metal, just to an even base that you can build up from. if you see different colors get a 1" feather between them.

just as a side note. I've painted 4 cars and had two painted by others. if you're just going for a shiny trail rig, the BEST looking trail truck I ever did was a 78 cherokee chief that I painted with Rustoleum Painter's Touch Sage Green spray cans. I spent $42 for a case of the paint, with coupon, at Homey D and used them all after prepping the truck as above. keep it even, keep it flat, and when you're done hand polish the hell out of it with 3M paint polish, then follow it up with the 3M liquid wax with the UV protectant. I swear by all that's holy that you could brush your teeth in the hood of that truck, and rock rash was fixed with the extra can I kept under the seat.

if you want to use an acrylic enamel or the like, rent or buy a good gun. the gun is more imprtant than talent, imo.