Many older parks are "legal non-conforming," which can be a trap if you plan to expand or replace homes.
Never take a seller's word; get written confirmation from the city or county.
Sellers often "cook the books" by underreporting expenses or overreporting occupied lots. Due Diligence Checklist for Mobile Home Park Operators
If the park is master-metered, you pay the bill and must collect from tenants. Ask if you can sub-meter to pass costs back to residents.