Terry,
Thanks for the great info. Forgive me if I jump on a minor point.
The road behind BCV is not a "service road". It's Epcot Resorts Blvd, the very same road you use to get to the Beach Club! After the Beach Club, it curves around behind BCV, goes under a tunnel beneath the walkway (and waterway!) to Epcot's International Gate, and continues over to Boardwalk and back to Buena Vista Drive, making a complete loop.
It may seem like a service road since there's little reason for guests to drive this stretch of road, so it's mostly used by buses, CM's and service vehicles. I actually ran along this road during our recent stay. Once you go through the tunnel there are sections with no sidewalks, so I'd recommend avoiding this route, instead running around Crescent Lake or following the jogging path maps they hand out.
Beyond Epcot Resorts Blvd, there are undoubtedly service roads that run behind the Canadian and UK pavilions, but I don't think you can quite see them from BCV, and in any case the noise from them is minor compared to that from Epcot Resorts Blvd, which is itself hardly noticeable if you have your balcony door closed.