The northwest coast of Kauai—which is itself the most northwesterly of the major Hawaiian Islands—is roadless and wild, where knuckle-sets of 2,000-foot-high cliff heads greet the pounding Pacific. At road's end past Hanalei is the Kalalau Trail, beginning its rugged, 11-mile journey to the Kalalau Valley, a pilgrimage for pig-hunters, adventure hikers, and erstwhile hippies. At peak times, nearly 500 people per day take a shot at the Kalalau, more visitors than at any state park in Hawaii other than Diamond Head. Parking can be a pain, and the first two miles of the trail can be a circus of wildly unprepared tourists.
Many options exist for visitors wanting to find the unpeopled places of Napali.
Most of the acess to Napali (The Cliffs), is way around on the other side of the island, off the highway that climbs above Waimea Canyon. On this road, most visitors go gaga (as well they should) at the pink-and-green walled canyon to the interior—and few visitors are aware that a dozen or more state forest roads and trails take off from the ocean-side of the highway. These routes go out ridge tops, which are separated by valleys and end at cliffs with birds-eye views.
You don't need a helicopter to get a look from the sky. Treks are from 6 to 10 miles, roundtrip, with an elevation drop of 1,200 to 1,700 feet on the way out. Mountain bikers can go nuts (though more popular trails, like the Awa'awapuhi and Pihea (which goes around the top of Kalalau Valley) are for feet only.
Kauai Trailblazer has many tips on how to avoid hassles when visiting the popluar Kalalau Trail, including nearby options. You'll also find directions and descriptions of the many routes less traveled in the upper regions of the Napali Coast. Final note: on the opposite side of the island from the Kalalau Trailhead, the cliffs end at Polihale State Beach—with Polihale Ridge towering above.