Your best bet is probably catching a cab over from Boardwalk or one of the other hotels. Otherwise, you can hop on a bus from HS to Ft. Wilderness OR take a bus to MK and take the ferry over to Ft. Wilderness.
From what I've read, the biggest complaint about HDDR is what a pain it is to get to. So, plan like, an hour at least I would say....
If you take a taxi from either DHS ( there are taxi stands near the buses) or an Epcot resort, you would only get as far as the campground entrance. You would then need to take the internal bus to Pioneer Hall. Same thing if you take the Ft Wilderness bus from the park.
Or you could take a bus to MK or Wilderness Lodge, and take the resort launch to Ft. Wilderness. The dock is just a few minutes walk to Pioneer Hall.
I'd allow 1-1.5 hours for transportation.
Wow. That is a lot of commute time. I am not sure if it will be worth it now.