We drove down to Florida in February last year, and will likely do the same this year. We overnighted in Fort Mill SC, just over the line from Charlotte NC. It was cold. Avoid hooking up to water. I would strongly urge you to follow the advice from the other posts. Just take some bottled water. Use rest stops as much as possible, but if you need to use the toilet, flush with RV antifreeze. Keep your rig winterized until sure of above freezing temps. BTW, it's likely to get near freezing tonight and/or tomorrow in northern Florida.
Bob