There are a few operators that do this day long trip. We took Valley Isle Tours. Our guide/driver was Tim. Super, Super job. Taking this tour is the ONLY way to go. If you decide to drive it yourself, you miss out on a lot, and the road is ROUGH. Hundreds of turns, lots of areas that are single lane. The views are wonderful, and you get SO much more on this tour. Many stops, nice lunch outside of Hana. Hana was a disappointment. The coach accommodates 12 folks in comfort, with soft drinks and water provided the whole day. Valley Isle does a round trip, where if you drive yourself, rental car companies don't want you to do it because there are stretches of road that are unpaved, and Very bumpy. Valley Isle picks you up right at your hotel or timeshare. We were priced up at 630am, and got back at 6pm. A small breakfast is included as well. For the price, it is a good deal, and they do have discounts, like senior discount. Driving your car is NOT the way to go to really enjoy this beautiful trip. Valley Isle tour will be the way to go.
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