How about the Northeast? We did Maine and Boston last summer and we all loved it. We started in Bar Harbor and Acadia but there are so many towns along the coast. Acadia is beautiful and very easy to do short hikes as your family likes. Bar Harbor has cute shops and restaurants. And lobster pounds! Portland is worth a day. We then drove up to northern Maine to do white water rafting and ATV riding. Off the beaten path but the rustic adventure resort had everything we needed and my kids love experiencing something different. After we had our fill of the Maine woods, we drove to Boston and spent 4 days there, hitting all the city highlights. It's so kid-friendly and easy to navigate. We are like SnuggleBuggles and tend to split our trips between nature and the city.
Mom to Two Wild and Crazy Boys and One Sweet Baby Girl