"The adventure begins where the asphalt ends" is how Princeville Ranch Adventures (PRA) promotes its two new off-road tours. Karin Carswell Guest, who owns the company with her husband, Jeff, found that was indeed the case in February, during a test drive of the Polaris Ranger Crew 800 in a remote area of Princeville Ranch. Roaring up a 700-foot hill, she bushwhacked weeds, shrubs and grasses standing as high as the steering wheel.

"I remembered going horseback riding around there when I was a kid and seeing a fabulous view of the mountains, valleys, Kalihi­wai River and the Pacific Ocean," Guest recalled. "Lo and behold, in a few minutes I was on top of the hill looking at that amazing view! That’s when I knew the Polaris was going to be a big part of our next exciting activity."

The 360-degree vista of Kauai’s North Shore is one of the highlights of PRA’s 4 1/2-hour Off-Road Adventure and 2 1/2-hour Off-Road Express, which launched in June and opened the lush interior of Princeville Ranch, a 2,500-acre working cattle ranch, to visitors for the first time.

All the pieces for the tours were in place: Travel agents and hotel concierges had spread the word about visitors’ interest in ATV tours, and PRA managers had been mulling over ideas for new offerings. Also, Guest knew there were scenic areas of the ranch that hadn’t been considered for tours because it takes too long to reach them on foot and horseback, and the terrain is too rough for vans to traverse.

Not so for the sturdy, powerful Polaris — the workhorse for the two off-road tours. "Our model seats six passengers," Guest said. "With two vehicles and two guides/drivers, we can take up to 10 guests on each off-road tour. That fits our business plan of focusing on small groups for a more personalized experience."

It took Guest, Jeff and Pat Nowak, PRA’s general manager, four months to map out and fine-tune the 10-mile route that both tours cover. A crew cleared paths through thick stands of invasive plants, and heavy machinery was used to build dirt roads and handle stumbling blocks that nature presented.

"For example, there was a steep hill on a narrow razorback ridge that required an off-camber turn in order to stay on course," Guest said. "It was a real challenge, but Jeff is an experienced road builder, and he reconfigured the path there and installed cable guardrails on a segment of it as a safety measure. That required time and creativity because we didn’t want to ruin the natural beauty of the setting."

During one break, visitors stand at the edge of the Hana­lei Ditch, built in 1922 by Kilauea Sugar Co. to divert water four miles from the Kalihi­wai River to the Kalihi­wai Reservoir. Back then the average daily flow was 5 million gallons, most of which was used for irrigation and to rinse cane at the plantation’s mill in Kilauea. The ditch was abandoned in 1971 when Kilauea Sugar closed.

Tourgoers stretch their legs on short hikes along forest trails bordered by ti, hala, ferns and strawberry guava, an abundant summertime treat. After a 10-minute walk down a steep trail, Off-Road Express groups pause for a snack at "Wedding Waterfall," so dubbed because numerous nuptials have been held there over the years.

The Off-Road Adventure ups the fun factor for its participants with a picnic, three hikes with eight stream crossings, swimming in a pool fed by a twin waterfall and gliding along two 400-plus-foot zip-lines connected by a swinging bridge.

Photography buffs keep their eyes peeled for cows, horses, pheasants, pueo (Hawaiian owl), wild pigs and chickens and nene (Hawaiian goose), Hawaii’s state bird. This time of year, a bonus is the kolea (Pacific golden plover), which flies 3,000 miles nonstop from its summer nesting grounds in Alaska to winter in Hawaii. The birds were spotted at Princeville Ranch a few weeks ago.

According to Guest, the off-road tours are activities the whole family will enjoy. Participants bounce across pastures and through forests with trees that are so tall and dense they block out the sun. Plus, there are plenty of dips, turns and climbs that are more thrilling than a carnival ride.

"The Off-Road Adventure mixes things up — going from hiking to zip-lining to swimming to picnicking with plenty of off-road excitement in between," Guest said. "A boy on one of the tours summed it up this way: ‘It’s like opening cool presents, one right after the other!’"

Cheryl Chee Tsutsumi is a Honolulu-based freelance writer whose travel features for the Star-Advertiser have won several Society of American Travel Writers awards.