I am as pro-rail as they get, but some of these lines are just not feasible. Bennington to Brattleboro includes two very substantial mountains. I lived on VT 9 in Woodford for a while, and I can tell you trains aren't going over that mountain. And tunneling would dwarf the nearby Hoosac Tunnel which is less that five miles long and took 135 lives during construction. Getting a line through Killington would be similarly challenging.

A more practical line which is absent from your map would run from WRJ through Keene and Winchendon using an abandoned right of way (push that rail-trail to the side) where it could connect to existing MBTA rail in Fitchburg. That gets you the Montreal to Boston connection along with Rutland to Boston. (Sorry, Cape Air.)

Living in Dorset, I'd love to see passenger trains come through Manchester, but some serious infrastructure work would be needed. For example, the line runs through the middle of the r k Miles lumber yard with trucks and fork lifts crossing the line all day. Unless you want passenger trains running at 10mph you're going to need some new grade-separated crossings along the line.