From Kanab, take Hwy 89 North to Hancock Road, and follow the signs to Coral Pink Sand Dunes State Park.
This is truly where the golden hour is in effect. Just after sunrise, and just before sunset, are when the shadows of the sand ripples are their best. The dunes are also open to Off-Road vehicles, so make yourself visible if any are around. Because of that, sunrise is best, before they hit the dunes. Camping is available in the State Park, right next to the dunes to get an easy jump on the day.