I have been looking forward to taking the Pinney Loop for some time, but knew I would have to walk about 0.8 miles down the Yellow Circle trail (Tunnel Road) from the parking area to get to it. The trail itself is 2.4 miles long, but add 1.6 miles to get to and from it if you walk from the parking area versus driving to the trail head -- not recommended. The trail begins on a former rail bed, where it is flat and very easy walking. The loop begins about 0.5 miles in (on the left). One could take the loop or continue straight -- I took the loop. The loop ascends about 230 feet to the "summit" before descending to where it connects with the orange square trail. There are no views at the top, but there is a lot of vegetation. Once the trail joins the orange square trail, it becomes relatively flat and wide and is again suitable for horses. When the two trails split, the Pinney Loop continues for a little bit on Tunnel Road and then goes back into the woods to resume walking on the rail bed. When you move into the woods again, look toward the right and you will see an old railroad tunnel going through the granite. It is worth the slight detour off the trail to see it.