Southwest of Encampment in the Medicine Bow National Forest, in the southwest corner of the Sierra Madres section of the MBNF, there is an epic OHV route. The trailhead access is on SR70 about 30 miles southwest of Encampment at Stock Drive (may not be signed).
The Snowy Range Mountains section of the Medicine Bow National Forest has miles and miles of forest roads open to OHV routes. Make sure you have the current Wyoming ORV permit.
Overall, Sierra Madres - Southwest is the 5th most popular OHV & 4wd jeep trail of all 8 OHV routes in Wyoming.