Consider also something larger than a RV "casita" lot, you may find greater value. You may find owning a southern property less expensive than RV snowbirding.
Don't know about other southern places, but recent check of real estate in former ranch areas of N Central Florida shows prices still depressed, a lot of smaller homes on roomy property where RV parking is OK, $70K to $90K for 1200-1600 sq ft. These are homes built in 50s through 70s in small towns not yet caught in the big snowbird boom that started in creeping north in the 70s.
These areas are not frost free, or on water going to the ocean or Gulf, nor in retirement colonies, all of which push prices up to where renting or owning a tiny parking spot makes snowbirding becomes. more of a RV thing rather than a winter home ownership thing.
I know other areas of the south, e.g. East Texas, SE Arkansas, southern Mississippi where small homes in rural small towns are even cheaper.
Very little of the South is where it never freezes, and those places tend to have very expensive real estate, Key West, San Diego e.g. But almost anywhere in the southeast or south central U.S. will be warmer than Indiana most of the winter.