my paint scheme for my off road cart is to paint the bottom with black rustoleum, then bed coating, the rest of the frame I'm going dark green rattle can, then spray with automotive clearcoat, I've use this process on bicycles, and it looks and holds up well as long as you get the paint right before clearcoat, sealing in garbage is still garbage. the bed coating is simply because its the only thing I've seen hold up other than powder coat, and its held up VERY well other than it fades with UV, but the floorpans and bottom sheet metal don't matter to me, it will hold up better than paint to sliding across trees, so I'm in.
If you want to try powder coating, get the HF sprayer, but order QUALITY UV safe powdercoat, or else it fade without a clearcoat, also plan on having to redrill/clear every snug hole as its thick tough stuff, but thats not a bad thing, just an FYI. the HF powdercoater works fine, but why risk having to tear it down and do it over with their low quality coatings. (I would use an HF paint sprayer, butif they sold paint I would avoid it, why risk all the extra work?)