The Waimea to Waimanu & back via the Muliwai Trail is an iconic multi day "hiking" trail here on Big Island Hawaii that is known for dangerous stream crossings, vicious elevation (~6000' gain, 16 miles), and usually takes at least one day each direction for "experienced" hikers.
Here are a few hiking accounts of it from major websites:
A fast out & back is on Strava: https://www.strava.com/activities/631445267/overview
Looking to attempt this mid December. Wondering what process I'd have to go through for my attempt to count.