KAILUA-KONA » A trip to the top of Kona's Hualalai mountain in former Swiss army troop transport vehicles is a once-in-a-lifetime adventure, said summit visitor Kristina Mauak after a recent visit.

She meant the 8,271-foot-high mountain with volcanic pits, random crags and 500-year-old ohia trees is extraordinary.

She also meant that the bone-banging ascent in open-air, six-wheel-drive Pinzgauer transports six miles up a jagged, dusty trail is something she probably won't try again.

But most of the 60 participants on the Feb. 7 trip forgave the jolts, and several used a single word to describe the trip: “;awesome.”;

Of the five volcanic mountains that make up the Big Island, Hualalai is the least known to the public.

The summits of Mauna Kea, Mauna Loa and Kilauea are all public land, and the Kohala Mountains have a public road across their upper slope. But the summit of Hualalai is owned by Kamehameha Schools, and tour provider Hawaii Forest and Trail is the only agency Kamehameha allows to make the climb, passing through four locked gates.

The Hualalai trip was part of a new, yearlong program of history, culture, biology and geology conducted by the Hawaii Volcanoes Institute, a project of Friends of Hawaii Volcanoes National Park. It was clearly picked to start the institute with a bang. Later events include hikes, bird-watching outings and photography trips.

The Hualalai adventure started innocently enough, driving up paved Kaloko Drive above Kailua-Kona to the 5,000-foot elevation.

Continuing up a “;very bumpy, rough road,”; in Forest and Trail owner Rob Pacheco's words, the convoy of six Pinzgauers reached an unnamed, 400-foot-deep “;fissure,”; or crack in the earth.

The enormous crack was created in 1801 when a long lava flow to the sea drained liquid rock out of the mountain, and the surface of the mountain collapsed into the space underneath, Pacheco said.

Pacheco announced that the tour would be a race to beat “;ehu wai”; mists to the summit. The mists form about midday every day and can reduce visibility to 200 feet.

They also signal that people have entered a zone known to old Hawaiians as the “;wao akua,”; the realm of the spirits, forbidden to most people in the past as well as the present.

The Pinzgauer convoy passed an old sheep station shack, cut through stands of Mexican pine and suddenly arrived in a shallow valley just below the summit cone.

There are actually three summits, Pacheco said, and no one can go to the highest of the three without special permission.

Trip participants hiked up to a slightly lower ridge holding geological instruments sending information back to the Hawaiian Volcano Observatory.

Pacheco warned it is easy to get lost here. Nineteenth- century travel writer Isabella Bird called Hualalai “;a complete wilderness of craters”; with more than 150 on the mountain's sides.

Sally Baque of Washington state was tongue-tied with pleasure. “;I've traveled a lot and I can't tell you; words escape me,”; she said.

A third of the people were from off the Big Island. Carole Kaapu flew from Honolulu to join the trip. “;Can you do this on Oahu? No,”; she said.

Two-thirds of the participants were 50 and older. Despite the jostling, no one was injured, and everyone got snacks on the way up, a meal at the top and snacks on the way down.

The banana bread got rave reviews, despite crumbling in people's hands as the Pinzgauers rumbled along. “;That's got to be the bumpiest banana bread I ever had,”; said participant Earl Yempuku.