How far of a walk is it between them both? Also how are the boats to epcot and dhs, are they overcrowded and how often do they travel? We have never stayed at either and looking for some info about moving around to both resorts and to parks?
BCV to BWV is about a 5 minute walk, I'd say.
Transportation from the Epcot resorts to Epcot & DHS is great. You can walk to either Epcot or DHS from either resort, or you can take the boats. Boats take longer generally, because they stop at both resorts and the Swan/Dolphin dock then go to Epcot. When staying at BWV, we took the boat back from DHS, but got off at the S/D Dock and just walked over the bridge to BWV. Very quick. The only time we found the boats crowded was on New Year's Eve going from the Boardwalk to Yacht/Beach, after the fireworks.
BWV to DHS walking = 10-12 minutes, add another 5 from BCV.
BCV to Epcot (International Gateway/WS) walking = 5 minutes, add another 5 from BWV.
We drove our own car to AK from BCV, so I can't speak to that. Our BC to MK bus experience was fine, but we went very early in the morning. We did have to wait about 20 minutes in the afternoon for a bus from MK to BC - because we usually drive, I found that frustrating, but I think it's a reasonable amount of time. Our BC bus shared with the Yacht Club in the afternoons - that changes around at different times of the year, and depending on which park you're going to.