Southwest of Buena Vista near Nathrop, the Alpine Tunnel / Hancock Pass route is a 20 mile OHV route along an old railroad grade. It runs beneath the Divide and over Hancock Pass.
Note: Colorado residents must register their off-highway vehicle with the Colorado State Parks (303) 866-3437. Non-residents are not required to register in Colorado, if they are registered in their home states. All off-highway vehicles must have an approved muffler and spark arrester. These requirements are subject to change so make sure to contact the Colorado State Parks prior to using your off-highway vehicle.
Overall, Alpine Tunnel / Hancock Pass is the 51st most popular OHV & 4wd jeep trail of all 61 OHV routes in Colorado.