As a coastal drive, the Hana Highway shares a number of similarities with the Seward Highway and Routes 1 in California and Maine -- after troubleshooting how you start the trip (fly in, rent a car?), you'll experience a route that snakes along a winding coastline, mountains rising sharply from the water on one side, and the water dropping away to the other. That said, if you or your passenger has a weak stomach, it might be a good trip to miss. There are approximately 620 curves along the 68-mile (109.4-kilometer) route, and 46 of its 59 bridges have only one lane, requiring frequent stops and starts.
If you go, plan to take your time and enjoy the many waterfalls along the way. Wailua Falls and the Seven Sacred Pools are popular destinations that offer photo-ops from the parking lot or, for the more adventurous, short walks to waterfall overlooks.