It was a nice walk in the woods on the Burnt Mills ATV trail. Thunder Swamp Spur trail yellow marker begins right after the bridge on the right side but it was so old and overgrown I did not feel like fighting my way through it. Maybe another time. To make the loop you have to walk on the Red Burnt Mills trail to yellow Thunder Swamp Spur trail and to orange Thunder swamp trail back to yellow and back to red.