From the junction of the Mauna Loa Trail
and the Observatory Trail
, head south and descend into the North Pit section of the caldera. Travel across the crater floor on smooth lava from the 1984 eruption. Peek down into collapsed Lua Poholo pit crater, taking care around the dangerously eroding edge.
Ascend the caldera wall, catch a glimpse of the cabin's roof in the distance. The Mauna Loa Summit Cabin sits at the rim at 13,250 ft and has 12 bunks. There is also a water catchment tank and pit toilet here. This may be the best sky you'll ever experience for clear stargazing without light pollution.
From the cabin and nearby waterhole, the historic Ainapo Trail descends the southeastern flank of the volcano, down to Highway 11, but it has since fallen into disuse.
Beware of altitude sickness, bring warm clothes, sun protection, excess water and food. Expect extreme and rapidly changeable weather. To avoid getting the bends, scuba divers should not ascend Mauna Loa within 24 hours of their last dive.