From POP. take the bus to MK, then boat over to FtW. As mentioned, it is a short walk up the hill to Pioneer Hall from the boat dock, about a 3 min walk.
From Epcot, bus to FtW/WL, get off at WL and take the boat over to FtW.
From DHS, bus to FtW/WL, get off at WL and boat over to FtW.
When you get out of the show/dinner, you may have two options for getting back to POP. If MK is still open, boat over there and take the bus back to POP. If it isn't, there will most likely be buses heading back to all the resorts from Pioneer Hall. CMs will ask which resort you are going to and then direct you to the correct bus. Each bus will make multiple stops at other resorts along the way.
I usually leave an hour for travel time. So, if you have a 7:15 ADR, you will want to be at HDDR by 6:45ish, you need to head out by 5:45ish. But, while some think that's a lot of time to 'waste' I tend to think of it as part of the fun. In fact, I usually head out sooner so I can take my time and not worry about being late.