"They're just a bunch of big old trees," Reggie grumbled. "Can we leave now?"
"Boring," Matt agreed.
We were walking along a paved trail at Muir Woods just north of San Francisco, looking at the giant redwoods. The towering trees, some more than 200 feet tall and more than 1,000 years old, were spectacular. But just seeing them wasn't enough to keep an active 10-year-old and his 8-year-old sister interested. Even worse, the level path we were following was much too tame to offer a hiking challenge.
I really blew it. We could have had a terrific afternoon exploring with the help of a free discovery pack from the visitor center. The kid-sized backpack comes complete with binoculars, magnifying lens, ruler, paper and pencil, bug box, net and a list of activities that would have kept the kids happily involved for hours, teaching them about the forest in the bargain. (Have you ever looked for things on the forest floor that are less than an inch long? Did you know ladybugs live for only a year?)
There were far more challenging hiking routes we could have taken, too. But I didn't know about the trails or the discovery packs because I hadn't asked at the visitor center when we'd arrived. I was in too much of a hurry to get going.
Many families who visit national parks have the same problem, rangers say. "It would be nice if people slowed down. They'd get much more out of the park experience," suggests Allison Campbell, who oversees education programs at Muir Woods. She notes that the park gets 1.6 million visitors a year, yet only 600 used discovery packs and many of those came with school groups.
"People want to see the park in five minutes," she says.
"We see a lot of exhausted kids and exasperated parents," agrees Candice Tinkler, Grand Canyon's education specialist.
It doesn't have to be that way. National parks today are reaching out to children and families with an array of programs and activities at large parks and smaller historic sites alike. The Parks as Classrooms program, a joint effort of the National Park Service and its philanthropic arm, the National Park Foundation, has reached more than 1.5 million schoolchildren since it started in 1992. In addition, plans are under way to join the popular individual Junior Ranger programs at many national parks into a national model.
These efforts come at a time when aging baby boomers are searching for more active and meaningful vacations -- that won't wreck the budget -- to share with the kids.
"There's a strong emphasis on kids in the national parks now," says Ms. Tinkler. "We want them to have a great experience. We want them to grow up understanding conservation and preservation and what the national parks are all about."
To get that message -- and have a good time -- it's not necessary to head to the biggest, most famous and most crowded parks. "Most of the 367 national parks now offer either Junior Ranger or other programs for children," says Corky Mayo, of the National Park Service. (Check for program availability before you go.)
Consider spending a day at a national historic site near your home or a weekend at one of the smaller parks around the country. The enthusiastic rangers are eager to show off what makes their locale special.
In Philadelphia kids can write poems at the Edgar Allan Poe National Historic Site and learn more about life in Poe's day (call  597-8780). In New York and New Jersey, you can go bird-watching at Gateway National Recreation Area (call  338-3575). Focus on cactus at Saguaro National Monument in Tucson (call  296-8516). Work hand looms at Lowell National Historical Park near Boston and see the way the "mill girls" from the factories lived (call  970-5000). Or play the part of a 19th-century judge, jury and lawyer and dispense justice at the Old Courthouse at the Jefferson National Expansion Memorial in St. Louis (call  425-4468).
These programs frequently aren't promoted or widely known. "Families have to seek us out," concedes Lowell Park spokeswoman Audrey Ambrosino. "We don't have a Disney World budget."
Now the park service wants to reach those kids who may not even be planning a trip. The National Junior Ranger program -- for which the service is seeking corporate sponsors -- will focus on activities children can do at home after writing away for the material. "Why should you have to visit a park to be a Junior Park Ranger?" asks Corky Mayo.
The Parks as Classrooms program frequently sends rangers into the schools to lead local activities. Contact the park nearest your home for more information.
Ask rangers how to make the most out of a visit to their park, and they'll urge that families relax and enjoy it rather than racing through the day to see everything. "The key is planning before you go," says Patti Reilly, who directs the Parks as Classrooms program.
Let the kids do the planning. They can write or call the park to see what family programs are being offered and when. (A good starting point is "The Complete Guide to America's National Parks," $17.95 from the National Park Foundation; a portion of the proceeds goes to the parks; call  533-6478.)
Talk about what everyone wants to do: Hike up to the top of a waterfall at Yosemite National Park in California, slide down a huge sand dune at White Sands National Monument in New Mexico, fish for trout at Glacier National Park in Montana. What animals do they want to see? The kids could even help plan which trails to hike.