The cache is hidden inside a cave that was formed by a collapsed lava tube. This spot is known only to locals. The trail starts out as a 4WD road that traverses pahoehoe lava. Someone was nice enough to mark the trail by spray painting white dashes on the ground. Follow the dashes until you reach the larger trees and you will notice a pink ribbon tied to a tree on your right. From there, follow the pink and blue ribbons (and intermittent dashes) until you come to where the word "tube" is sprayed on the ground.
From there, go about 50 feet until you see a depression in the ground. Carefully wade down into the tube and enter the cave on the west side. You don't need to go into it very far. You will notice a flat, mossy rock that forms a platform of sorts. Start looking for the cache from there. Good luck!