Here are some additional travel tips related to some specific destinations. However, the bottom-line tip set out at the end is of a general nature:
1. When in Boston, do the Duck Tour. It's a hoot. Also, staying on Newbury Street is a nice choice. Many great restaurants and other stuff easily walkable to, including the Duck Tour.
2. When driving from Boston to and in Ogunquit (Maine), expect many detours getting out of Boston and many delays on the way and many delays when you get there, and watch out for oblivious pedestrians walking out into the streets willy nilly. Also, there's no reason to eschew using the Express Pass given that it costs $3/day and $20/max per rental. And there's certainly no reason getting off at the last exit before the bridge into Boston to try to avoid using the Express Pass because you'll end up in a very scary place and find yourself taking many turns to scuttle back to the bridge.
3. When in Ogunquit, Hunchback of Notre Dame might not be as bad as you had feared, but it's safe to say it's not as good as Hamilton on Broadway or even Book of Mormon on the road, and if you go, sit as close to the back as possible if you care about the safety and integrity of your eardrums. You can't walk or just sit on the Marginal Way too often, but eating lobster more than every other night might be a bit much. Caution, if you want lobster, do not go to any restaurant where you will pay $35+--instead, having it delivered cook for about $10@, and while you likely never heard of it, opt for soft-shell lobsters that look identical, taste better, cost a little less, and do not need clack crackers.
4. When in New York, be sure to visit Croton-on-Hudson (it's gorgeous with amazing ninja squirrels and deer and gophers and all kinds of lush vegetation) and Brooklyn Heights (it's beautiful and quiet and peaceful and the promenade and what's being done under it as just amazing). Battery Park is definitely worth the visit and every restaurant where you have good company is more than worth it. And, if you want a thrill of a life-time, spend $5 to ride the Sea Glass Carousel. Be sure also to visit the Hudson Valley by car or by boat or both. The 9/11 Memorial is beautifully done, but watching tourists treat it just as they would a Battery Park fountain is a bit disconcerting. A late night drink at Grand Central Station is a treat, especially watching strangers hook up with each other either before they head home or perhaps instead of heading home.
General Trip: If your travels involve meeting up with people you love and otherwise truly enjoy being around, it does not matter when you go. That said, if your travels are taking you to what are considered tourist destinations, such as Boston, Ogunquit, and New York City, if it works for you, you might find it advantageous both price-wise and crowd-wise to avoid tourist season, especially places where tourist season means a lot of people schelping along alot of children of all ages.