Agree with some of the others on Maine and on avoiding Boston. Look hard at staying in the Portsmouth NH/Kittery Me area either on your way to Acadia or on your way back. This puts you about 50 miles from Salem, and Boston, easy day trips with the toad. And is also a lovely area on its own. Even Lake Winnepasaukee is a fairly easy day trip from that area. Cape Cod though is still 2plus hours away so if Plymouth and the Cape are on your itinerary, skirt Boston, preferably on a Sunday Morning on your way there.