We just stayed at a pretty campground in Cape Cod called Cape Cod CampResort & cabins. It has beautiful sites along the woods and an adult pool. It is a little pricier than the average campground and they do charge extra for extra people, etc. but we would definitively go back. If you bring your car, you are fairly close to the ocean, beaches and quant little towns as well as stores. If also has a dog park for big and small dogs which we appreciated having 3 dogs with us. The people were friendly. We stayed in a premium site and we loved our spot.
Their website is: www.capecodresort.com