I would also probably opt to take the bus from OKW to DHS and then either walk (about a mile) to BWV or take the boat. In terms of the boat from DHS to BWV, it goes from DHS to S/D, then to YC/BC, then to BW/BWV. You can also get off at the S/D and then walk to the BW (~5 minutes at most). If you take the boat all the way from DHS to BW/BWV, I'd allow about 20 minutes.
The buses from DTD to BWV usually also include the Swan, Dolphin, Yacht Club, and Beach Club. If you're going at an off time it might not be bad, but if you're traveling during a busy period, it might mean waiting for more than one bus or being crammed into a bus like a bunch of sardines.