The Contemporary will be your best bet for a consistently quick trip to the MK because of the walkway. Staying at a hotel on the loop (Contemporary, Polynesian, Grand Floridian), there's always the possibility that a monorail is arriving just as you're walking to the station. Of course, it's also possible that you just missed the monorail, which will add roughly 10-15 minutes to your travel time as you wait for the monorail to loop around again. Whereas with a walk from the Contemporary, you know it's a 10-15 minute walk, no guess work.