The answer to the OP question "Park Models RV or Not?" can be elusive unless one realizes that there are two types of park models build to different standards.
The A.N.S.I. Park Model unit (under 400 square feet) is built to comply with the R.P.T.I.A. ANSI A119.5 Standard for Recreational Park Trailers. This type of unit is licensed and titled as a Recreation Vehicle.
The H.U.D Park Model (over 400 square feet but not more than 500 square feet) built to comply with the H.U.D. Manufactured Home Construction and Safety Standards. This type of unit is also licensed and titled as a Recreation Vehicle in Florida only.
ryoung