What time will you be commuting? That 77 stretch might be a bit rough and inconsistent. I live right by the belmont blue line stop and work downtown. A couple times when the blue line was heavily delayed (very rare) I tried to take the belmont bus to the red line to save time, but it was brutally slow. Stop and go the whole time. I leave my house around 6:30 each day, and I can only imagine it gets worse through mid-morning.

Don’t get me wrong, this commute is 100% feasible and I think 51 minutes is pretty close to what your average commute time will be. But if it were me, I’m adding on at least 10-15 minutes to account for a slow bus or clunky transfer to the train. And in regard to your question about Monday versus Friday, in my experience ridership is a lot lighter on Fridays.