I sprayed the bottom half of a coach outside w/o a paint booth or anything. Did it in sections early in the day prior to the wind coming up. Used 2 part acrylic enamel. Hardest part, because the temps were in the low 50's when I did this (to avoid insects) was coming up with the right amount of reducer (almost double the suggested). When that was figured out, the rest of the job went very quickly and turned out awesome!
1997 37' HR Endeavor, 275hp Cat, Freightliner
03 CR-V Blue Ox, Ready Brake