OK, I just took a better look. Here's the shortlist in my opinion.
If you are not a New Englander and wanted mountains/inland then (not in any particular order):
Von Trapp at Stowe: Stowe is the premier New England Ski area, but is kind of quiet with not a lot to do for young kids. Great hiking/skiing, and the Von Trapp Lodge is really 1st rate. Other things to do: Ben and Jerry's tour, Mt Mansfield Auto road...
Moosehead Cottages: I described this already. This is the north Maine Woods...physical beauty, I thinks the most physically beautiful inland spot in New England, and I love it- but young kids will be bored if they don't appreciate outdoorsy stuff.
Manchester VT: The Equinox is beautiful. Very different than Von Trapp. Manchester has more to do than Stowe, better shopping and eating, and is "closer" to the Bromley water slide park which is great for ikids. Again, not a lot of kid stuff.
Loon/Lincoln NH: This is a bit more touristy. There are a few ski areas here and close to North Conway, the shopping/eating mecca. Quite a few scenic drives and much more kid stuff than other places above. There is actually a big waterpark, Santa's Village which is a cute little year-round winter themes amusement park, water tubing on the rivers etc.. if you look around you will find things to do with younger kids in this area, but the hotels and dining/shopping facilities aren't as upscale as Manchester or Stowe.
If you want coastline:
Newport: both of the listed options are nice, I prefer the Harbor Club. Newport is awesome in the summer, I wouldn't go otherwise, and it is my favorite summer coastal destination in New England. Mansion tours, the nicest beaches in New England some say, great dining and shopping, incredible nightlife, and its all in a very tight little area unlike the Cape. So the beaches are 1 mile from the heart of it all etc....you can also day-trip to Block Island or even the Cape or Martha's Vineyard, or even Foxwoods/Mohegan Sun Casinos.
Bar/Southwest Harbor: A bit more subdued and quiet. Quaint upscale villages with nice seafood restaurants and some great lobster pounds. Quiet at night. Maybe a movie theatre is about it for little kids. But again, if you hike/bike/horse-ride/just appreciate physical beauty this is as beautiful as coastline gets east of the Pacific coast!
Cape Cod: Lots of little villages and nice beaches, shopping and dining, but it is spread out. There are a few little cheesy water parks/mini-golf things. Day trips to Nantucket the Vineyard, or Provincetown if you are not homophobic are possible. The cape has a lot, but I find it to spread out. Very nice golf courses if you play.
Just my opinions here....