First wash the cart well with warm water and simple green. Then assuming that there is no body work, or imperfections in the paint like checking you can go in with 400-600 grit on a DA sander with an interface pad and sand down the orange peel on everything that is a flat surface, stay away from the edges. Your goal is to remove orange peel and flatten your work surface so sand until you can no longer see shiney spots but do not sand through the paint. This will only work on painted surfaces for textured or plastic surfaces and any remaing shiney spots get sandfix and a gray scotchbrite with a bucket of warm water with a little bit of simple green in it, soak the scotchbrite in the water, wet the surface with the scotchbrite and then put a silver dollar amount of sandfix on the scotchbrite and go over the whole surface with a medium presure adding sandfix as necessary, just make sure you are not marring the plastic if you are your using too much pressure. I usually sandfix everything after I sand it as well it will increase adhesion. Wash cart again warm water and a little bit of simple green, the better you wash the cleaner the paint job and the easier the mask job. Use a plastic cleaner first then use a water based cleaner to remove static and remaning dirt. If there is no bare plastic then go with a quality base coat then follow with the same brand clear, some companies have a flex additive to add to their clear and some just have a flexible clear coat. If there is bare plastic I strongly recommend priming with three to four MEDUIM coats, letting it dry for a few days, sanding off the orange peel then doing your base clear, whatever you put base on needs to be at least 400 grit with an interface pad on a DA. Normally you need to add flex additive to everything but base coat as it is normally flexible. I know I got pretty deep into it but i think this will provide you with the best result the easiest way. Remember that the work surface should be at least 65 degrees and to watch your recoat times so you dont get any reactions your parts supplier will provide you with all the material information as far as dry times and ratios. Mask everything off as overspray gets on everything, tack before basecoat and you should be able to tack between base and clear you can test this by making sure its dry on the masking paper before putting a big streak in your cart. This info can be transfered to a single stage paint just don't tack between coats and be sure to add the flex addive to it. As far as paint its up to you, I know what people will tell you but I was never able to get the quality out of lower cost paints on the otherhand its a golf cart. Urethane paint is the best paint for you, and which ever brand you go with use it all the way through. Some have a seperate plastic adhesion promoter you put down on bare plastic before primer, and some have an all in one adhesion promoter and primer. I have not had great luck using sealer on bare plastic then going directly to paint it comes out smoother with a primer surfacer, sand, then paint. Again sorry about the book and dont rush the paint between coats, Good Luck