I agree with Rolf. If someone was like his tenant, it seems ok to Grandfather in, but not continue with any new tenants.
Depending on roads in your park as to what damage might be done. We have concrete roads and concrete parking pads. I had a truck driving man and wife buy a home in our park, first home in on the left. Bright Orange Tractor. He asked about bringing it in. I was very polite, but completely refused. We had this discussion before him buying a repo from me. He understood and has complied so far. He parks in a parking lot across the street when he is in town. I did not want it in there because that big ole thing is just unsightly if trying to keep a park looking nice or trying to turn one around. And it is heavy and the roads might be ok, but the parking pad would surely suffer. And you know turning that big thing around he would have to drive off in the grass causing ruts.