The Amtrak Connects Us report proposes reducing travel times from BRK-BON, but doesn't outline any specific proposals or goals to make that happen. Realistically, what would be the most attainable way to shave ~20 minutes off of BRK/POR-BON? PTC outside of MBTA territory to get speeds above 79 seems like the most straightforward way to make that happen.
This is one of those situations where it's unfortunate that B&M abandoned the Eastern Route, which was much straighter than the Western Route and could have supported higher speeds.
I'm not sure where or how you shave a full 20 minutes off the BON-POR route (maybe by straightening some curves and upgrading the rails from 115 LB to 132 LB, all of which would be very expensive), but shaving 20 minutes off the BON-BRK route becomes pretty easy simply by moving the Portland station onto the mainline and raising track speeds between POR and BRK, which have always felt unnecessarily slow to me.
If they're still planning to add a stop in Falmouth, you'd have to add 5 minutes to the running time... so the 20 minute reduction becomes a 15 minute reduction.