Army Special Forces veteran Ray Knell cautiously walks toward an old bison before giving it a wide berth; Photograph by Ben Masters Ray Knell, a Green Beret and Afghanistan war veteran, called me in January 2015 seeking advice on how to ride a thousand wilderness miles from Colorado to Montana along North America’s Continental Divide. Two years ago, I completed a 3,000-mile ride using wild mustangs across the American West as part of the documentary Unbranded, so I was eager to share my experiences with Ray for his journey…