If I remember right from our trip in June, the bus goes directly to MK after picking up at BWV. They make the circuit through the Swan/Dolphin, YC and BC on the return trip from MK though, so that's the long leg of the trip. You can always choose to get off at Swan/Dolphin and walk back over to BWV though. .They may provide more direct routes at busy times (e.g. opening/closing) though. Additionally, when we were on the bus with just a handful of guests mid-day a couple times, the driver asked where we each were going and only stopped there. (Must have been other buses doing pick-ups because he didn't seem concerned about missing pick-up stops.) I don't know what the DD Disney route is; we drove there.
Have a great trip!