I'll be travelling with DH and DS, who will be 2 at the time of travel. I've never been to the States.
We like the beach, but not to sunbathe on, and DS is too young for theme parks. We want to see "things" and like exploring. We'd probably like the facilities of a resort but the flexibility to do our own thing if we want.
I've a feeling that I want to go to New England, the mountains, and may be combine with a city break.
California is wonderful as it is so diverse. Beaches, mountains, vineyards, Grand Canyan, take your pick! Quite a long flight though with a two year old. My DH always says Boston would be a fab place to take the DDs, he travels there on business. We loved New York but do not think that fits your criteria.