My experiences with the DTD bus wasn't too great from AKL - it always seemed to take ages (however, I never had to wait long for the bus). I think it was closer to 25 or even 30 minutes. I timed it when we were there and I remember that it was significantly longer than the MK bus ride which was between 17 to 20 min.
To get to the Boardwalk: You can also take the bus to AK and then get on a BWI bus. It might be a bit faster since the boat is not that fast...
While it isn't as scenic as the boat, it should be more efficient. I think the trick is to try to know which parks ar close to which resorts, so hopping from one resort to the other all parks close to one of those resorts would be a good transfer point - except Epcot for the Epcot resorts