Screw the red car I wouldn't want to get squashed by that bus.

I LOATHE crossing the BU bridge. I do it sometimes when accompanying my wife on her commutes to BU, in which case we ride the sidewalk, which is used by many as an extension of the Cambridge side bike path. It's a conundrum though- tons of pedestrians, many at least as aggressive as the worst of the drivers, a windy bridge, uneven road surface. I've resigned myself over the years to slow to the speed of the pedestrians, take a big dose of patience and roll across on the sidewalk. It makes it real tough though when you want to go straight off the bridge down Brookline Street to Central Sq.. To do that I'll resign myself to riding on the road part of the bridge. I hammer hard across, hold my lane by being right out there, keep my hands on my brakes, my head up and maintain or increase my speed as I head for the light. If I get the light, I hold the lane by getting right in the middle of that right lane (not at all an easy thing to accomplish) and when it changes I try not to let them run me off (or over), I just get out there and make sure I'm visible. But you have my sympathy if you use that bridge every day and want to cross it at anything more than walking speed.
Use good judgement on that bridge and be careful!- you're right to be concerned and not alone in finding it difficult to come up with an appropriate strategy to deal with the multiplicity of problems it presents.

As for my commute- I didn't have to work downtown today. My commute was from Newton to Wellesley and I took Washington Street, which sucks to tell the truth but I survived it. I could've come up with a more creative (and slower) route but I left late and had to haul. On the way back I stopped at Harris Cyclery (made famous by Sheldon Brown) bought a couple of spare tubes for my commuter and came home.