The Cobblestone Loop is a lariat-shaped extension off the Glenwild Trail, with a connection at the top to the newer Flying Dog trail. Most riders don't do Cobblestone alone as a ride, but combine it with Glenwild or Flying Dog. But you CAN drive to the loop.
The loop itself is in a heavily-wooded area. The top of the loop nicks a new development, where (as of 2007) roads are in place, but no homes. It's pretty, and the trail is nice, if short.
The connector to Glenwild isn't as scenic, but it's smooth and easy riding. The bottom portion near Glenwild is fairly flat with sagebrush and grass. Near the loop itself, you're in a small canyon among small cottonwoods.
If you started on Stealth and went over the top of Glenwild clockwise, look for the trail at mile 4.4, about 1/2 mile after descending to the sage-covered valley. Go L uphill on Cobblestone.
If you went counterclockwise around Glenwild, find Cobblestone in sage brush at mile 3.8 as you approach the hills. Go R uphill.
0.0 Fork off Glenwild N40 44.756 W111 31.279
0.6 Cross paved road N40 45.204 W111 31.558
0.9 Fork Cobblestone Loop N40 45.365 W111 31.750
Left 1.4 Cross road N40 45.549 W111 31.793
1.7 Fork R (L=Flying Dog) N40 45.704 W111 31.573
2.4 L at fork, bottom of loop
Right 1.6 Fork L (R=Flying Dog) N40 45.704 W111 31.573
1.9 Cross road N40 45.549 W111 31.793
2.4 R at fork, bottom of loop
3.3 Back at Glenwild trail
At the I-80 Park City exit, go north (left) as you exit, then immediately turn right on the frontage road (Bitner Road). Continue east until the road turns L (north) and becomes Bitner Ranch Road. About mile 3.1 from the freeway (shortly after passing the golf course), the road will veer L (approx N40 44.79 W111 30.595). At mile 3.4, turn left (west), N40 45.016 W111 30.885. Watch for the trail to cross the road at about mile 4.1, N40 44.929 W111 31.433. Park and start uphill. If you continue on the same road, keeping left at forks, it will curve around from west to east and intersect the top of the loop at N40 45.549 W111 31.793.