I feel the further north you go on Vt 100 before you cut west the better..
I agree w/ rt 8 thru Mass to 100 in Vt. Once in Vermont these are a few of my favorite routes...
1. 100 north to Vt 30 west/north to Burlington.
2. Continue further up 100 north then at Ludlow take 103 to 140 to 30...