All of the Magic Kingdom resorts use the monorail to go to Epcot. Sometimes there are buses from the Magic Kingdom bus loop to other theme parks, but I think it has limited hours. I am pretty sure it starts in the afternoon after the morning rush to parks from the resorts is over. You would need to ask a transportation CM at MK. You could to go another resort and take that Epcot bus, but I am not sure that would save you time.