I-295 or I-95 to the GSP. I did the GSP on a Sunday and it was a decent ride. Alternately you could take the I-287 ring.
From here you have a choice.
1. Tappan Zee Bridge to I-684 to I-84 to I-90 (Mass Pike) or
2. I-87 to I-84 across the Newburg Bridge to I-90
The TZ Bridge is under construction and usually has a lot of traffic, so I'd opt for #2. Depends on the time of day.
From I-90, take I-290 to I-495 to I-95. Stay on I-95 all the way to Bangor then 1A and 3 south to BH. Alternately, you could take I-295 in Brunswick and pick up Route 1 to BH. Only take this if you have a lot of time.
Jerry & Jeanne
1996 Safari Sahara 3530 - 'White Tiger'
CAT 3126/Allison 6 speed/Magnum Chassis
2014 Equinox AWD / Blue Ox