Mauna Loa Observatory Road: 5.9 mi (9.5 km) from Mauna Loa Observatory to Summit Cabin, 6.4 mi (10.3 km) from Mauna Loa Observatory to actual summit. Stays are limited to 3 consecutive nights per site. Backpackers to Mauna Loa should be adequately equipped, experienced in wilderness/high altitude trekking, and physically fit.