Taking the bus from DTD means you have to get to DTD first. This takes up time. I would walk to Poly from SOG, then Monorail to MK, and then bus from there to the BC.
I try to avoid transfering at DTD at all costs.
Another option is walking to TTC from SOG and then Monorail to Epcot. You could then walk through Epcot and out the International Gateway and over to BC.
Both options will work, just depends on how much walking you want to do. Walking through Epcot also requires park admission, so that may affect your decision. We have AP, so I never think about those things.