Not sure about what you mean by "RV friendly," but one of the best and busiest RV beach destinations is Myrtle Beach. It is not RV friendly in the sense of driving your RV around (traffic gets dense and parking is rare) but is a place where you come in, park your RV for the duration, and rent something (golf carts commonly) for getting around.
Nashville is several hundred miles from any coast, and New Orleans is not particularly RV friendly, although there are many good locations on the Gulf Coast, from Biloxi, Mississippi to Carabelle, Florida with the Destin area being a top beach destination.