We will continue deeper into the Garden Isle's lush interior, until we reach the Keahua Arboretum inside the Halelea Forest Reserve - here the pavement gives way to a rough dirt & gravel 4x4 track. This is the only public road on the island that leads so far inland, taking us very near the center of the island and close to the headwaters of the North Fork of the Wailua River at the base of Mount Wai'ale'ale.