Wilderness Giant Edition 4: Ordeal. Wilderness Giant Editions, #4

Back before the poison of civilization had corrupted the wilds of the Rocky Mountains, brave mountain men struggled to carve a life from virgin land. But few of these hardy souls had ventured beyond the mountains to the Oregon Territory and the vast Pacific Ocean. Lewis and Clark, Kit Carson and other living legends blazed trails through the unknown regions, often leading settlers. When one party of pioneers disappeared, Nate Kind and his mentor, Shakespeare McNair, were hired to track them down.
The perils along the way were unending, but if Shakespeare and Nate survived, they would earn the greatest reward imaginable - the courage to live free.