Ray Knell, right, and Ben Masters look out over the Yellowstone River as they make their way to camp along Yellowstone Lake; Photograph by Michael Ciaglo I woke up to the not-so distant howl of a wolf in the deepest backcountry location in the Lower 48. The half light of coming dawn allowed me to barely see our five horses and two mules standing at attention seeking the source of the deep howl. Another wolf joined the chorus, this one further away, up by the headwaters of the Yellowstone River and…