Windy roads were not a problem for Kanale, our driver. He's a pro. A jolly man who entertained and informed us. We had plenty of stops, some for shopping, some for exploring, some just to admire the scenery. I had scheduled an empty day in Maui that I'd go back and hit the high points along the road to Hana but I decided not to risk trouble on the winding, narrow and sometimes wet, roads on the route. I strongly suggest you bring a dash cam and request it to be discreetly mounted on the windshield of the tour bus. You'll be glad you did. Summary of things to bring: Camera and/or GoPro, dashcam, mask/snorkel (preferably the newer unibody variety), cash, towel, swimsuit. Sunscreen is optional, you probably won't be in the sun long enough to get burnt. Swimming stops are sorta brief, 20 minutes or so.