If you are thinking of North Conway, I have been going to Saco River Camping Area for more years than I can remember. We tent camped there for years but now tow the "house" behind us when we go. It isn't fancy and costs a bit more than state parks but has clean rest rooms, showers, and friendly people. They have Canoe and Kayak rentals and will bus you to a put in location in the morning for a leisurly ride down the Saco River to the campground.
http://www.sacorivercampingarea.com/