I did the TF Green to S. Station (last stop on line, but one stop after Back Bay) for four years.
A few times a month I would do the Amtrak route from PVD - I found I had to arrive extremely early in the AM to get a parking spot. Cheap as it is to park there, early bird gets the worm. I ask was able to choose my days to be in office, and they were flexible. I recommend being flexible beyond T / W / Th - those are likely the same days chosen as everyone else with such flexibility. Randomly, a Friday in the office that ended with a train ride home was a calming start to the weekend. I knew when I got off the train I was done for a few days. More life balance than budget/convenience I suppose. Get your Amtrak tickets or pass as advanced as possible. Also, just to say you’ve done it, consider doing the commuter rail now and then. Builds character, not that I assume you have none. It’s one of those gotta try it’s if you’re going to be part of the Rhody to Boston masses.