West of Park City, just on the outskirts of Summit Park, a lonely stretch of forgotten road snakes across the gentle slope off the shoulder of I-80. After branching off the westernmost road in town, the irregular and deteriorating pavement slithers along Parley’s Creek, a thin and crumbling line between a seven-lane transcontinental artery and the largely unspoiled wilderness of the mountains beyond. This forgotten path, simply labeled “Unnamed Road”...