I've hiked this trail many time and also have hunted for wild boar along it and in the valleys along side the ridge. I always enjoy coming back to Waimano. When you hike a trail enough times you begin to notice things that you missed on other trips. It is a long trail, perhaps the longest on O`ahu at 7.5 miles ONE WAY!!. If you are new to hiking you'll enjoy it as it is not the typical up and down ridge hike. Rather it follows a contoured route slowly gaining elevation until you are looking down into Waihe`e Valley. This is not to say it is easy, but it is not as hard as say its neighbor the Manana Trail.
Here are some links to some of the other times I've hiked this trail.
Here is a two section map (the trail is to long to show it on one map w/any detail) showing the route to the summit as well as portions of the Halapepenui Trail to the right of the Waimano Trail.
The trail begins at the end of Waimano Home Road in Pearl City. You park outside the gate and follow the fence line for a while. Along the way you will see a "road" leading down on the left. Do Not take it. Keep along the fence until the "real" trail begins. You will be following the heavy dashed line which runs along an old ditch and tunnel system that was once used to bring irrigation water to the sugar cane fields in the Pearl City area.