I don't live there. Most of my mothers family lives in Maine. I spent a week in North Conway a few years back for some fishing time. We did drive up "Moose Alley" and into Canada and back through Maine for something to do while we were there. Beautiful country!
This is a link to the NH dot maps. The dotted lines are class 6 unmaintained roads. Pretty much all the legal off roading is either private land with permission or the class 6's; which by the way are pretty good from mild to wild. http://www.avenza.com/
This one is for Avenza PDF maps. The app I loaded the state maps into. If you create the folder you put the maps in as a collection it will follow from one town to the other. I have the entirety of New Hampshire and some of Vermont.