Hiked Nottingham Mountain via Neville Peak Loop and the red marked trail. Near the summit there is a red marked trail that goes up to Nottingham. Once you get up to the open side of the mountain, the true summit can be reached by following the snowmobile trail to the right if facing the peak. The true summit is near the chimney.
https://www.alltrails.com/explore/trail/us/new-hampshire/neville-peak-loop