Most of the time, the Boardwalk, Swan and Dolphin share a bus to MK and AK, with pick-ups in that order. Y&BC have their own bus to MK and AK...again, most of the time. Exceptions might be super-early in the morning or other off times, like the middle of the afternoon...then, all five Epcot resorts might share a bus.
The DTD route also encompasses all five resorts, plus Typhoon Lagoon, and takes forever...an hour at least! On the way back, it's even worse, because there's a wait while the drivers change shifts. Unless you're an extremely patient person, I highly recommend a taxi to and/or from DTD.