Princess typically starts in the Epcot parking lot so you could look at picking a resort closer to that part of property. Epcot Resorts (Yacht/Beach, Boardwalk, Swan/Dolphin) will require a bus to the start line (and probably finish line) since Epcot won't be open to walk through. Personally I always pick Pop Century because of it's convenience to ESPN Wide World of Sports for the expo and bib pick up. It also never feels too far getting to race morning from there. But that's just me (and my bias towards Pop Century in general showing).