I agree that driving can be more convenient, but it depends where you are staying and where the road closures are for a particular race (ie driving from an MK resort during the half or full at MW would not be possible unless you left extremely early). For your situation, just follow the directions in the race guide and you'll be fine. We drove from Margaritaville for Princess and it was super easy. We left at the time the first buses were picking up at the resorts to avoid any traffic issues, but once you are there you can nap a little in your car, eat breakfast, finish putting on a costume, etc.