Thank you for the input and advice. Here's my update and I'll post details here in case anyone else is in this situation in Ohio in the future. Again, this information applies IN OHIO, so don't take this for any other location. But in Ohio, the real authority on mobile home parks is the Ohio Mobile Home Commission (http://www.omhc.ohio.gov/). I own another park in Ohio and the commission does the annual inspections, but I didn't realize they basically are also the last word on legality of a park in Ohio. If the OMHC recognizes the park as a legal park, it's legal. There was a court case that went to the Ohio supreme court a couple years ago where a city was trying to tell a park owner that since the park was non-conforming, they could no longer bring homes in. Essentially the supreme court decided that as long as the park remains in use as a park and doesn't cease operations, then the owner has the right to continue to operate it and do what needs to be done to operate it successfully (including bringing in new homes). The authority of the OMHC to have jurisdiction in such matters was also established. So, in Ohio, as long as a park has not ceased operation AND is recognized as a park by the OMHC, it is fully legal, despite any zoning that may have been imposed after the park was in operation. All this info came from the Executive Inspector/Investigator of the OMHC, who was very helpful.