National has a location at swan/dolphin, close to BWV, so you could rent a car at the airport for one day, drop off after checking in to BWV, and walk back to your room. Not sure what the rate comparison would be, but it would make for easy transfer. Then you could either rent another car for return to airport, or get a 1 way towncar, etc. There might be some discount information on National car rentals at mousesavers website. Good luck and have a great trip!