Very technical, very rocky mixed-use trail. I explored these trails often, and rarely road the same way twice. Trails closer to the road are an intersecting network of hiking trails and singletrack. Follow the hiking trail norh, up some seriously steep climbs and through typical New England rock gardens to the crest of the ridge. Continue north and the ridge-line trail takes you to North Amherst. Hop onto the roads, or turn around and retrace the trail to get back to where you started.
From downtown Amherst, continue east on Main St, which becomes Pelham Rd for less than a mile. Just after a small bridge over a creek, there is a clear trailhead on the left. Gravel parking for a few cars, but if you live in or near Amherst, it's best just to ride there.
http://www.singletracks.com/item.php?c=1&i=1058