I have no personal experience, but I know someone who bought one and then expanded it/fixed it up. They ran it for 6 years I think and it provided them a good income and helped them to build their dream home. They managed it themselves, the wife working inside--it has a gas station and little cafe/shop. The husband fixed everything outside and took care of the pool/waterslide, etc.
They sold it a few years back and were very relieved, bc it was hard to sell and it kept them very busy. They financed the sale to someone who ran it into the ground and then defaulted after 2 years, so they had to come out of retirement a few years ago to retake ownership/fix it up and they have been running it since, rather unhappily unfortunately. They had to leave their dream home vacant to live on site at the rv park. So for them it was a mixed bag I suppose. It seems to do pretty well and always has a decent number of campers staying there.