There's also a bus from MK to WL, which is usually a bit faster than the boat. Of course, the boat is more scenic, and the walk from the boat dock into WL is pleasant, if a bit longish.
If you're traveling early a.m., the boat from MK to WL starts running 30 minutes before the MK opens. Before that, you can take the bus from MK, or stay on the monorail to the Contemporary, where the boat to WL starts at 6:45 a.m.