Don't do the Road to Hana if you were nervous driving in Sedona. I've done both and Sedona was a piece of cake. Cannot claim the same about the Road to Hana.
Of course, there's no reason to do the entire road. Once you've seen one waterfall, you've seen them all. So drive a few miles in, perhaps to the Arboretum and then turn around. Ho'okipa Park is a great place to stop and enjoy the surfers/windsurfers and it's on the road to Hana. Make reservations at Mama's Fish House for lunch. Expensive but delish. And it's on a beautiful beach so ask for a table with a view.