I am not an RV person, but I did join two very close friends of mine a couple of years ago, on a 3-and-a-half week RV drive and liked it. One of the places we stayed at for a few days was Golden Isles RV Campground, in Brunswick, GA and I really liked it. It was clean, quiet and fairly close to the shore (may be 5 mile) which made it easy for us to also visit Jekyll Island and St. Simon.
Like I said, I am not an RV person and I am not sure what specific criteria true and tried RVers use to judge these places, but out of the others we stayed at, this stuck out in my mind.