Not sure. If you can get a good fare with SW, I would just book with them and not worry about doing RAC at CBR. They may be ready with extra storage room by then, but no one can give any promises.
Being able to use RAC is a huge plus, granted. But, if I can get a good fare, and not drive so far to the airport, but not use RAC, then I'm going with the airfare.
I use both TFGreen and BOS....BOS is actually closer, Green is exactly an hour away from me, BOS is about 40 mins. But I go with the airline that has the best fare for the times I want to fly. If I can check my bags at the resort using RAC, that's a plus..but not a deciding factor.