Pawtuckaway State Park, New Hampshire
I have lived in New Hampshire my whole life. As a child we would go camping every single summer. Sometimes we would go multiple times a year. This is a tradition I have kept with my children. One place we love to go is Pawtuckaway State Park, http://www.nhstateparks.com/paw.html.
Pawtuckaway State Park is located in Nottingham, NH. This is a campground for everyone, it has hiking, swimming, boat rentals, fishing, and biking. There are trails through the woods to hike on, and bike on.
Inside the park is Lake Pawtuckaway. It is a cute little lake that is great for swimming. The lake has a great sandy beach to play on, or just relax in the sun.
Two years ago my daughter was five and we went to "the beach", (that's what she called the lake. For 2 years I got away with not going to the freezing beaches of New england.) This was the first time we took her canoing. We rented a canoe from the boat rental shack, they also supply the life jackets, and we went out on the lake. She loved it, we were out there for 4 hours.
Much to our surprise when we returned, you rent the boats by the hour. So either bring extra money with you or keep track of time when you are boating. Pawtuckaway is great for a wide range of campers. They have a variety of camp sites, and although they do not have hookups, they welcome RV's onto any of the larger sites.
I do not believe they are open yet but, last time we were there they had started construction of small cabins. That will be great when they are open. They have running water and everything that is needed at the camp store. They have great clean bathrooms with showers for the use of the campers. It is a great family friendly campground you are sure to enjoy; we sure do!