Lebanon's Boston Lots is an incredible place to ride. Over 30 miles of trails ranging from mellow to meltdown. Easily many days of riding and exploring.
The land manager is Dartmouth College. But the trails are maintained and loved by the Upper Valley Mountain Bike Association who's webpage has an excellent trail description as well as for many other local riding hotspots.
UVMBA is a great group and if you do more than casual riding here it would be a good group to join.
Additional information is at MTB Project.
At 1030' the high point in the Boston Lots is Burnt Hill. You'll do a lot of climbing, some quite technical to get there. Expect to do some exploring and after a few rides you'll come up with your personal favorite trailsand routes. There's a lot at Boston Lots.