The Man of the Forest by Zane Grey

Accidentally overhearing a plot to kidnap the niece of a prominent rancher as she arrives from the East, Milt Dale springs into action. He comes out of his splendid isolation to protect Helen and her kid sister, Bo. Leading them away from manmade danger, exposing them to unaccustomed rigor on mountain trails, Dale imparts his rugged philosophy. Beyond the forest, Beasley and Snake Anson are still waiting to carry out their evil plot.