A federal court ruling affirmed that RV parks or campgrounds fall under Fair Housing regulations. That means a park or campground can't have a "no children" policy. They can restrict children if they fall under one of the 4 exemptions. 1. 55+, which still isn't completely restricting children. 2. Clothing optional. 3. Fraternal or religious non-profit organization where use is restricted by membership contract. 4. If activities are occurring openly and without restrictions where children would be prohibited by law from attending.
RV parks and campground do have the right under federal regulations (states may say otherwise) to use creative space arraignments to keep areas kinda separated so long as they are not reducing the services or quality to those with children and not turning anyone with children away.