Make sure you are at the front of the resort to catch your bus and don't wait at the bus stops for the theme parks. Usually the marathon runner buses stop at one spot and go from there. Usually they are charter busses with drivers who don't know about all the bus stops. And sometimes the bus drivers don't know how to get to the start. My husband and his friend got on a bus once and the driver started going towards the airport until all the runners got him turned around and going the right way.
Good luck with your run. You should have plenty of runners going from CSR.