I know of three in eastern Oklahoma, two in Arkansas delta country and have seen at least one along highway 9 in eastern Texas and one in eastern Kansas. Whether or not that is on the way to Florida depends on where you are coming from, my route to Florida takes me through SE Oklahoma, across Arkansas, and through the Mississippi Delta.
These are all small locally-owned motels, not part of any chain, and what they typically have in common is a local need to house a seasonal work force. Some workers stay in the motel, others bring there homes with them. It is also common in these areas for municipalities to operate low cost RV-only campgrounds to meet the same need. These will be busy in season, empty off-season.
Most lower-end motels that have work-crew clientele will also allow you to rent a room for the night, and have parking for your RV, but not for you to stay in it.
You might also find "overnighter" RV hookups or small RV parks behind gas stations, depending on where you are in the country.
Tom Test
Itasca Spirit 29B