Estes Park was hardly more than a post office in 1899, when young Joe Mills first saw Colorado's Front Range. A would-be Robinson Crusoe, Joe scaled peaks, watched wild animals, hunted and trapped, and generally roughed it in the region that would become Rocky Mountain National Park in 1915.A Mountain Boyhood, the true story of his adventures there, is as rich in human as in natural history. Joe meets a colorful bunch of early settlers, living for...