Baby Boomers Spark Boom in Family Adventures : Parents are introducing their children to a wide variety of outdoor experiences, from llama trekking to kayaking.

Paul Rosenfield hiked up an Alaskan glacier, kayaked in the rain alongside whales and sea lions and saw bald eagles and bears in the wild . . . all before he was 3.

Now 4, he’ll be making his second trip to the Alaskan wilderness later this summer with his parents and 8-year-old brother.

“It’s such a wonderful experience. Who else would you want to share it with but your kids?” asked Paul’s mother, Los Angeles attorney Sandra Kunsburg. “I would hate to leave them behind.”

Across the country in Greenwich, Conn., the normally sedentary Scharff family is still raving about the horseback trip they took last spring in the Arizona mountains. “It was so different from the pressures of our daily lives,” explained Louise Scharff, a Manhattan magazine editor. She and her husband and sons, aged 10 and 13, rate the rugged camping trip “right up there with Disney World.”

“We want to do it again,” she said, despite her miserable spill off a horse into an icy stream and a hailstorm one night that was so cold she couldn’t get warm. Not even the weather bothered the children, of course. “It was a big adventure that we could have together,” Scharff said.

These days, that’s what growing numbers of baby boomers are looking for when they plan their family vacations--particularly with grade-school-age and teen-age kids. It’s passe to do nothing but lounge around the pool. It’s also passe to race across the country from national park to state forest to historic site.

“Adventure travel for families has really taken off,” said Dave Wiggins. His 22-year-old Boulder, Colo., company--American Wilderness Experience, which he claims is the oldest and largest domestic adventure travel company--is now booking hundreds of families every year into nearly 100 ranches and back-country programs. (Call 800-444-0099 for information.)

At roughly $2,000 to $2,500 for a family of four (excluding air fare), such adventures don’t cost any more than Disney World and some trips are considerably cheaper. “Nobody is balking at the prices,” Wiggins said.

It should not be surprising, then, that so many outfitters are working hard to tailor trips for families: sending them canoeing in Minnesota, kayaking in Mexico, snorkeling in Hawaii, llama trekking in New Mexico, white-water rafting in Colorado, biking in California and hiking in Maine.

Those with especially well-padded wallets may opt for more exotic locales. Seattle-based Wildland Adventures, for instance, offers itineraries that include trekking in Nepal and scuba diving in Honduras, where families can spend the week swimming with dolphins (800-345-HIKE).

An East Coast company, Overseas Adventure Travel in Cambridge, Mass., also explores exotic locales through such trips as a Serengeti safari and a Galapagos adventure emphasizing respect for the ecosystem (800-221-0814).

And the new edition of Pat Dickerman’s comprehensive book, “Adventure Travel North America” (Adventure Guides, $19), offers nearly 300 pages of options. She advises families traveling with children to ask tour companies to design custom adventure trips with less arduous itineraries geared to the capabilities of children.

Backroads, a Berkeley, Calif., cycle-touring company, doubled its family offerings from 1992 to 1993, a spokesman said. Backroads added mountain biking in Idaho, California and Germany to its repertoire of adventures accessible to kids. Trips start at a few hundred dollars (800-BIKE-TRIP).

OARS, based in Northern California, one of the country’s oldest white-water rafting companies (800-346-6277), is also expanding its family options by offering less-rugged river trips.

Similarly, Bill Dvorak’s Kayak and Rafting Expeditions of Nathrop, Colo., have special “kids go free” rafting trips and offer a price break on other trips for large families (800-824-3795). Wilderness Adventures of Ely, Minn., touts special packages for those who want to canoe with their children (800-843-2922).

To help families plan, there is a new Hearst magazine called “Family Adventures.” In its first issue (spring/summer 1993), stories include “Choosing the Right Adventure” as well as features on family camping, fishing with kids, kite-flying and even scuba diving.

Taking the Kids invites reader questions and comments about family travel. Address them to: Taking the Kids, 2859 Central St., Box 119, Evanston, Ill. 60201.