I hiked this in early April 2010. The stone walls in the forest are very extensive and well worth the hike, especially if it is early spring, late fall, or winter, when no ground coverage obscures them. Photos of walls along the trail.
You can extend the hike by just under a mile if you include the red-blazed Furnace Loop Trail as well. Or, park at the trailhead by Hall Drive and Orange Turnpike, and just visit the furnace without adding the extra hike. Google Maps: Park at A and walk to B.