We are planning to drive from Detroit to the east coast via Niagara Falls this July 4th for a week. I would appreciate suggestions on what to see and where to stay in the Connecticut, Mass., Rhode Island, Maine area. We have three girls 11, 13, and 15. Other than my husband skiing in Vermont, we have not been out east. Thanks very much.

This is a pretty ambitious trip for a week if you want to go to more than one or two locations. It's a solid days drive from Niagara Falls to the coast i.e. Boston.
In general, Boston would be the top draw if you want city life and many attractions followed by Newport though that is probably less attractive with kids (touring mansions gets old quickly).

What about Cape Cod, Nantucket, Martha's Vineyard? I could use help with prioritizing based on ages (11,13,15) of girls. Thanks again.

For history: Mystic Seaport in CT, Old Sturbridge Village or Plimoth Plantation in MA. Tour one Newport Mansion. You have to drive thru NH to get to Maine, spend a day at the water park in Portsmouth or do a harbor cruise. If you go to Boston: Museum of Science including the laser show and IMAX theater and Boston Duck Tour. For beach time in Maine, York Beach is a family place and it is traditional to watch the saltwater taffy machine at the Goldenrod and buy a box to take home and take a long walk up to the Nubble Lighthouse for an ice cream. The water is going to be cold then but kids don't seem to mind. I would also try foods the area is famous for i.e. fried clams. If you go to Boston, eat at Durgin Park. Walk thru the North End for some Italian pastries. If it's Friday or Saturday, see the pushcart vendors in Haymarket. The girls might not be interested except for a brief look and get some fresh fruit. The Indian Museum at Foxwoods in CT is terrific and not to far from Mystic. To keep it fun for the girls, try to do things like fly a kite on a beach, explore tide pools, go to a 4th of July parade.
Hitting just the Newport/Mystic area or Boston/Portsmouth area will be plenty.

its hard to help prioritize with no hint of your interests...cities? culture? beaches? hiking? mountains? history? shopping? All of these things are well represented in the 4 states you list.

Frankly, I wouldn't go within 10 miles of Cape Cod or the Islands over 4th of July weekend. The traffic is going to be abysmal, and with such a short trip its not worth it. If you are interested in the beach, maybe Hampton Beach or, as dfrost suggested, York Beach. The beaches in Rhode Island near Newport can be pretty nice too.

I'm just looking for a fairly quick overview of the area -- including history, beaches, etc. I don't think we would spend time shopping since we are so limited. How does Martha's Vineyard compare to Nantucket? Thank you.

Well - you've asked about 5 entire states. And to see much of anything you would need about 3 weeks. Since you're going to be spending a day getting to the Falls -a day therer - I presume and a day getting to the coast - you only have a couple days befor eyou need to start home.

So - pick if you want beach, city, history or whatever and people will be able to give you one place that will give it to you. Agree that the Vineyard or Cape Cod on July4th Weekend will be mobbed - assuming you could still find somewhere to stay.

The problem with New England is that there is so much packed into a few little states. A living history museum can be fun and educational but one would be enough. The Cape has many more sandy beaches than the whole coast of Maine but we only visit the Cape off season because of the traffic. Maybe you should have your family vote on one place to go and then focus on what that area has to offer. If you stick to the coast, Newport to Boston to Portsmouth NH is an area with a lot to offer that doesn't require a lot of driving. If you pick a travel route, that would also help. I live in and love New England but I still haven't seen everything. Sometimes we do Sunday drives just to discover new things. Recently we drove up a mountain road that's only a half hour away yet a road we've never been on before. (Super views and a great place for a picnic.) When we took our son and niece to Plimoth Plantation I don't think they enjoyed it as much as a go-cart place we happened across. One of the nicest New England experiences we've had is attending a fiddlers picnic at a nearby church. The event was not widely publicized, just one of those gems that tourists don't get to see.