It looks like a low-polygon model of a bus from a Grand Theft Auto game set in a fictionalized version of Boston.

I bet that would be a fun game.

One problem would be that it ran in the street, not in its own right-of-way, and I don't think that would fly today, but the bigger one, the thing that killed it, is the Newton I-90 interchange. Before the Pike the A branch crossed the railroad tracks on the Washington Street bridge, which carried traffic in both directions. After the Pike, that bridge was one way northbound for cars, but two way for the trolleys. In theory, so long as traffic followed the lights vehicles wouldn't get stuck on the bridge blocking the trains when the southbound trains had the green. In theory.

I have concerns about West Station too, because it's very close to Boston Landing, and having stops super close together slows things down.

Once upon a time that was the Green Line A branch, which ran to the intersection of Galen St and Nonantum in Watertown. The 57 bus more or less follows the same route.

We told them that in 1770, 1773, 1775, and 1776, to name just a few occasions, but they just don't seem to get the message.

FRI would be my suggestion as well. We're fortunate to have a lot of labs in the area and I'd trust any of them with a normal roll, but none of them are experts in developing 80+ year old film.

That stretch of Memorial is closed Sundays between April and November (and Saturdays too, at least for this year) so you can stop by another time. Some info here.

East of the BU bridge you shouldn't have problems. On the Cambridge side, Memorial Drive will be closed to cars between Western Ave and Elliot Bridge Saturday and Sunday, so you can ride there. Otherwise, expect to see a lot of pedestrians on both sides of the river between the BU and Arsenal St bridges. The heaviest crowds are usually on the Boston side between Western and Arsenal, you'll have to walk your bike through parts of that area, especially between Elliot Bridge and Arsenal.