Also, there is currently some construction going on at the Magic Kingdom bus stop. Therefore, the direct bus from WL to Magic Kingdom is temporarily suspended. It now runs Ft. Wilderness, WL, TTC. So you would then have to take a monorail or Ferry to Magic Kingdom.
So for right now, the boat is the best option!! (Also, there are smaller boats that run WL, Ft. Wilderness, Contemporary). You could take the smaller boat to Contemporary then walk to MK.