Sure you can camp in either place in the winter. (heck, we're in Michigan at the moment).
Typical RV's should be good down to the mid 20F's without any special consideration. We've spent time with temps in the teens and one time down to -5F (not recommended but can be done).
As long as the heat is on, you are generally OK with not winterizing, though if you can keep the waste tanks empty before a cold evening that's a good idea.
The pink RV antifreeze is safe for the water system and if you get a sip of it, it won't kill ya but it does taste nasty. You don't generally put until you are done using the water system.
If the Carolinas or northern Florida is OK, depends what you are looking for. We love 50-60F days as it's nice to get out and go for long walks with just a windbreaker. If you are expecting 70-80F, you need to head for south Florida...of course so is every other snowbird so places are full and prices are high.
The other thing to consider is if the parks are open. The further north you go, the more likely they close in the winter (example: the place we are in Michigan closes at the end of Nov and there is only one other park that is open in southern Michigan...which was already full)
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV