Total Rebuild of a 1979 Dodge Class C

hey Driver dats a hard question to answer without seeing the surface but I wld think a good polyurthane with a good primer base for alum wld do just fine ,,its a little pricy but its very user frindly and dries very fast then a good clear coat ovet the whole unit wld make th paint job last for years,,Im assuming here that the back is covered with alumn like the rest of the unit...this question is a little confusing as it sort of states you are gonna paint the back with a different paint from the rest of the unit poly will do fine for the whole unit just make sure you use a good primer made for alumn...aand remember preping is the most important part of the paint job ,,it goes like this 20 hours of prep and abt 1 hour of painting,,,any kind of dust or ruff will ruin the paint job..from lookin at the unit it looks abt a week of machine and hand sanding to get it rite you need a good D?A sander it runs on air from the compresser or you might get an electric D/A from Lowes..