Manana Trail (4 mi) is about 4.0 miles long and located near Pearl City, Hawaii. The trail is great for trail running and normally takes 1-3 hours.
Just the lower 2 miles of the Manana Trail, this route goes out to the picnic table / camping site, and the trail is in great shape. Good for walking, good for running.
Bring water; there's none along the way.
Tell someone where you're going; you can take this route and not see another soul.
Bring someone with you.
There's a lot of shade, but that's no excuse for skipping the hat and sunscreen, especially in dry season.