Last year we did this trip. I took I-77 into Charlotte, Nc. Picked up I-85. We stayed around at Georgia RV park for a few days just of I-85 visiting my sister. From ther I took US 441 into anthems then picked US-129 into I-75. This route avoided Atlanta and was a good road to travel.
On the way down we stayed at Fort Chiswell in Wytheville, Va. There is also a KOA there as well. Easy on and off of I-77. Georgia RV park only $25 a night. From there we stayed in Ocala Florida for a few days visiting friends. There is a lot of RV parks in that area. From there we went Fort Meyers Beach to the Red Coconut. Spent 12 days there, then onto the keys. In the keys we stayed in Marathon at the Jolly Roger.