Not far from the southern tip of the Big Island, the entrance to Kahuku is about an hour’s drive from the main park entrance, but the two areas are contiguous, joined at the summit of Mauna Loa.
These photos are from a guided hike in Kahuku that I did a while back. The hike went through fairly dense old growth Hawaiian forest that had been spared because it was in a steep gully and thus not suitable for clearing for pasture. There was no real trail.
Currently this part of the park is closed because trees with Rapid ‘Ōhi’a Death (ROD) have been found in the lower part of the park and the goal is to prevent it spreading to other areas.
For more information on the Kahuku Unit of Hawaii Volcanoes National Park, go to nps.gov/havo/planyourvisit/kahuku-hikes.htm or bigislandhawaiitravelguide.com/places/puu-o-kahuku-at-hawaii-volcanoes-national-park.html