Kauai's north shore is where the 1950s classic "South Pacific" was filmed, and its yellow-sand beaches and aquamarine waters have been luring tourists ever since. In the summer, calm waters are filled with snorkelers, while winter months bring waves to some of Hawaii's most underrated surfing beaches.
Bottom left of upper photo is the Wahina River, which drains the valley where the last of Hawaii's ancient people, the Menehune where counted in a 20th-century census. From there, the highway twists through a tropical arboretum, passing Lumahai Beach (of South Pacific fame), and reaching Haena State Park—site of beach-side camping and near Tunnels snorkeling beach. The Kalalau Trail along the Napali Coast starts a couple miles past Haena, where the highway ends.
Helicoptering over Kauai will give you the best perspective of the island's dramatic beauty. Blue Hawaiian helicopters is a good choice. When it's time to test the trails, the Kauai Trailblazer should be in your daypack.