Watch for a scenic viewpoint at the hairpin turn. Park in the lot there. The trailhead will be to the right as you're facing the ocean. Long single track contouring the Koolau Mountains. Spectacular views of the mountains, ocean, and lush tropical valleys.
Final third is mostly fast and downhill.
Ends up in Waimanalo for pick up or ride back. This trail is a bitch if you ride it when it is wet or right after it has rained a lot. It has got to be by far one of the most beautiful trails i have ever ridden and it is definately challenging for your skills. There are areas that require technical ability as well as a set of good ol' fashion brass cajones. BE warned ahead of time that wild boar will attack you if you are not paying attention.