Easy mode: If your body doesn't leak and you don't have rust to solve first, make a trip to Tractor Supply/Rural King/etc and get a couple gallons of Majic tractor Paint (https://www.tractorsupply.com/tsc/pr...ety-blue-1-gal
) in a color you like. Paint everything that isn't the roof with it.. Note it dries very slowly, you need to wait a full day before applying a second coat and 2 days before doing anything else with the painted surface.
For the roof, you can get Rustoleum Professional oil based enamel at Home Depot. (https://www.rustoleum.com/product-ca...ective-enamel/
) This stuff rolls on easy and dries very quickly, you only need to wait an hour between coats. I put 3 coats on my bus, and its so reflective you never want to be on the roof when the sun is out!
Before you paint you want to clean the surface really well. I used a power washer, some simple green, and a big scrub brush.
Lesson learned - Don't put tractor paint on your bus if it's going to rain within the next day. I'm still repairing that mistake.
if you're somewhere sunny like Florida/Texas/Arizona/etc, all of your heat issues will be caused by the sun hitting the metal. White reflects best, the more white the better. We used IH White tractor paint for the sides and the rustoleum gloss white for the roof.