You're right...beginning of December is late to be starting from the Chesapeake and end of August is peak hurricane season. Insurance coveverage may be an issue for you if you venture south of the Chesapeake. I know you can get it but it may cost a lot more...still they insure all those boats in Florida!
As to where to stash the boat for a few months that won't be too cold when you get there in December...I am thinking that Wilmington or New Bern NC might be good places to keep your boat. Both are off the ICW and a bit more inland which I think is good if a 'cane did come close and both have several marinas, good services and are safe places. Wilmington is closest to SC and placing yourself there would be the equivilent of leaving the Chesapeake around 11/15 which is certainly not too late. It also leaves several of the more open sections of the ICW behind you so you wouldn't have to worry about nasty weather much. Obviously...there is no guarantee in the Chesapeake OR anywhere in the southeast that a 'cane won't get you but I'd say Wilmington or New Bern are reasonably safe unless you just get damned unlucky.
If you really want to get south...then I'd recommend Isle of Hope Marina just south of Savannah as the location is good and they have an enclosed basin and well cared for facility. Problem there is that you' d have about a 2-3 week trip in peak 'cane season to get there.
As to the Bahamas...I think you'll be really pleased with the choice! Get a copy of the Dodge Guide to Abacos this winter if you want to get really excited about it!! Merry Christmas!!