I'd take the bus to the MK since it drops you off in front and you can avoid any delays at the TTC especially at park open/close where it can be quite a wait for a Ferry Boat or monorail (assuming it's running). To me it's also a question of how much stuff you pack to the parks too. If you have strollers, etc the buses can be tough. Personally I'd drive to the other parks. I never ride the parking trams since we can generally beat them back to our car at DAK, DHS and Epcot anyway.