I used to RV. You do indeed go from campground to campground, but not like it sounds. Look in your local yellow pages for a KOA campground. Visit it and ask for information about working at the campgrounds in lieu of parking fees. Ask for a KOA magazine and look in the back for employment listings. Here is how it works: You stay at a campground and (usually) work 4 hrs a day, 5 days a week in their little camp store, or wherever they need you. In return, you get your trailer space, water, sewage, and electricity free. Usually, you stay as long as you wish, then contact another campground, set up your employment, and you are off again. State parks also offer something of the kind...in this case, you are hired as park host. I was never a park host, so I don't know if there is a salary involved with that. Go for it. You will love it. I would not have come home if I could still see well enough to drive. Oh, and "must haves"? A microwave, a computer, and a dog!
Edit: I forgot to mention that KOA also has a work assignment deal where you plan out an itinerary, and they set you up a work schedule from one campground to another. Another club you might want to check is Good Sam's.
Here is a link that will help you. Included on this site is info on working at the camps (lower left of page) http://www.koakampgrounds.com/