The best place to be in January is Florida. There are so many things to see and do that you can stay busy for the whole month but like trop-a-cal says campsites often have to be reserved ahead of time, especially in the most popular areas. That said we recently spent two winters in Florida without making reservations. The key to this is to seek out smaller county and community parks. They don't have many amenities like pools, WiFi and club houses but they're usually in more natural settings. This site is a good source for information about public campgrounds -
http://www.ultimatecampgrounds.com/uc/index.php If you want to reserve sites go here -
http://www.reserveamerica.com/ By the end of January you can start heading west. The history of the south centers around the Civil War and plantation life of the 1800s. The national park sites are very popular -
http://www.nps.gov/index.htm The history and culture of the Cajuns in Louisiana is interesting. You may be able to catch a Mardi Gras parade if you're in the area in early March.
Search the state tourist sites to help with planning and, if possible, send for brochures of all the places that you may be interested in seeing.
http://www.usa.gov/Citizen/Topics/Travel-Tourism/State-Tourism.shtml The Florida link isn't working. Try here -
http://www.visitflorida.com/en-us.html I have a blog with information on the places that we visit. Our trip from Florida to Texas starts here -
http://rollinginarv-wheelchairtraveling.blogspot.com/2012_01_01_archive.html Have fun planning!