Banjo by Robert Newton Peck (1982, Hardcover)

Banjo and Alvin started hiking up a lonely mountain road toward the deserted spar mine, a place so dangerous every kid in town had been warned to stay away from it.

But Banjo knew it was where they might find the old hermit Jake Horse, the famous person they had chosen for their school project.

People whispered about Jake but nobody was brave enough to talk to him.

Before the day was out the two boys were to learn a lot about danger and bravery, and friendship, too.