There are a couple of ways to do it--we never have a car at WDW so this is the way we usually do it.
Take the bus to the MK. Once you arrive at the MK, take the boat to the WL.
Or you can take the boat from the Dolphin to MGM. At the front entrance, take the bus to WL.
There really is no easy way--we usually plan on about an hour of travel time. I don't think it's ever taken us that long but then we have plenty of time to wander at the WL.
Have a great trip!