My DH and I visited Plymouth Mass last summer and I agree it is a great place to see.
Also, if Rick Steves has a guide book for that part of the country, I recommend it. We are planning a trip to the UK using his very helpful advice. He has all kinds of info I didn't expect - like how long the bus/train rides are, where the laundromats are (cuz he recommends only 5 outfits per person - saying [in effect] to pack light and wash often) as well as info on "out-of-the-way" tourist attractions.
Enjoy!