We just did the HDD during our stay last week, we did it on Sunday the 18th at the 5pm show. It was a good time, though I am not a chicken fan, but the ribs were good and the beans fantastic. Anyway, we took the bus from BW to MK, then the boat to FW. We hit everything at the right time, the bus came within a few minutes of our arrival at the bus stop, and we just about walked onto the boat for the trip to FW. Having all the modes of transit alligned got us there in about a half hour. I can see having troubles if you miss one of the connections - one night we were going to the MK and passed a crowd coming from the bus stop. Must have been the MK bus, as we waited a good while for the next one. You may have a wait at MK for a boat also.
Another alternative is to walk thru Epcot and take the monorail to the MK, which may be slower, but the monorail may run more regularly, but you have to go to TTC first and switch. Another way is to walk to either MGM or Epcot bus stops and take the bus to either WL or Contemporary and take the boat from there. And another way, though it will be getting dark around 5 is to take a bus to WL and walk the path, it is right about a mile from the bus stop to the Pioneer Hall.
When we returned from the HDD there was a crowd waiting for the boat back, but there is also a boat to the Contemporary, and that is a short walk to MK from there, even shorter if you are just going to the MK bus stop.
Another hint, when returning to the BW from MK, you can take the Swan bus, as it is a short walk from the Swan bus stop to BW, and quicker, as the BW bus stops at the YC first, then the BC, then BW. I guess this is also another alternitive to getting to the MK as well.