We visited Medway ME just for the chance to see what the interior of Maine was like.  We stayed at the Pine Grove Campground and really enjoyed it.  It is a rustic campground, with large sites and we had one right along the river.  Here’s my review on Yelp: 

http://www.yelp.com/biz/pine-grove-campground-medway?hrid=7elCJxNd-T5sTPuV5lJybA