I wouldn't have guessed that Mass Ave would be the *good* route.
You went right by, or through, my alma mater. Whose cross country team often ran (presumably still does) to / in / from the Fells. Which is why I can claim to have been running in the Fells since 1970.
Although there was a bit of a gap. I don't recall running there between the mid-70s and about 8 years ago, when my dear daughter had established herself in the Boston area and got me to join her in a loop of the Reservoir (orange) trail (while my speedy son-in-law did Skyline in the same amount of time). I've since been visiting the Fells every few months, most recently
Friday. Which brings me to the point that ties back in to your log entry: Every single time I go there, I make a wrong turn (or several). *Every* time. Even this most recent time when I printed out and carried a copy of the Fells trail map. (I was about to say the MDC map but that just shows my age again.)