I dont think the words "cheap" and "paint RV" go together well. You have a vehicle that has 6 - 7 times the surface area of a large SUV. That means 6 - 7 times as much materials and prep time.
Spraying such a large vehicle requires talents beyond the regular painter, it needs a specialist that knows the materials and how to keep them wet long enough to coat, yet dry quick enough to not run.
It needs a special paint booth; the overspray from such a large shot would be astounding. A booth that size isnt found many places.
If you can limit your repainting to just areas of damage, and bring the other older finishes back to life, you might get away with it fairly cheap.