CUSTER, S.D. -- "Let me know when you see a buffalo," Matt said, not believing we'd ever spot one outside a TV set. He was engrossed in his Game Boy in the back seat -- too busy, he said, to watch boring Black Hills scenery through the minivan windows. That changed in a hurry.
"Look!" Reggie said excitedly, pointing to the side of the road where a huge, furry brown bison -- that's the correct name for the 2,000-pound animal -- was nonchalantly grazing. A few miles farther, we slowed to let another lumber across in front of the car. Custer State Park, where we were driving, has one of the largest bison herds in the world: 1,400 in the 73,000-acre park.
The video game was forgotten. And the kids were so involved looking for wildlife they forgot to fight. Before we pulled into the Mount Rushmore parking lot, we had spotted antelope, bighorn sheep, mule deer and rabbits, as well as more bison.
The wildlife, I confess, were a lot more exciting to the kids than was Mount Rushmore National Monument, stunning though it is with its 60-foot-high sculptures of George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt jutting out of the mountaintop. I did my best, explaining the sheer magnitude of the accomplishment of sculptor John Gutzon Borglum, who devoted the last 14 years of his life to the project. One eye is 11 feet wide; a nose is 20 feet long.
We visited the sculptor's studio -- work stopped soon after Borglum's death in 1941 -- and I told the kids why these presidents had been chosen: Washington to represent the birth of the Republic, Jefferson for the idea of representative government, Lincoln to represent our permanent union and equality for all, and Theodore Roosevelt for the 20th-century role of the United States in world affairs.
"You mean we can't climb up to the top?" they said in shocked disappointment. They were more interested in getting back to the parking lot to see how many different license plates they could find: Most states were represented on the summer evening we visited.
There's no doubt that Mount Rushmore remains the most famous site in the Black Hills, and one of the best-known tourist attractions in the country, drawing 2 million visitors a year. Many vacationers on their way to Yellowstone make it their only stop. But they're missing a lot -- especially if they're traveling with children. The Black Hills area of South Dakota also contains long, spooky caves; the site in Hot Springs, S.D., where more than 100 prehistoric mammoths perished; the rich fossil deposits; the rugged countryside of Badlands National Park.
We lingered for a couple of days, staying in a cozy cabin with a fireplace in Custer State Park, the second largest state park in the country, and wished we'd had more time. (Call  658-3530 for reservations.) This is "Dances With Wolves" country (Kevin Costner's Academy Award-winning epic film). More than 50,000 American Indians still live in South Dakota, and it is a wonderful place to teach children about their history and culture.
One good place to start is 17 miles southwest of Mount Rushmore at the Crazy Horse Mountain Memorial, the largest sculptural undertaking of its kind. Keep in mind that the Crazy Horse memorial is not a government project. The sculpture is financed primarily by admission fees ($12 a carload) and the efforts of the family of the late sculptor Korczak Ziolkowski, who dedicated more than 30 years to the project.
When finished, the carving of Dakota Chief Crazy Horse will be 563 feet high and 641 feet long: All four heads at Mount Rushmore would fit inside Crazy Horse's head. (Call  673-4681 for more information.)
We saw workmen up on the mountain, though they weren't blasting the day we were there. There is also the impressive Indian Museum of North America at the base, showcasing 20,000 artifacts.
The kids were impressed with the hands-on area where they could grind corn, feel pelts and go inside a lodge. Being able to take home a piece of the rock seemed to mitigate their dismay at once again not being able to climb the mountain.
That's one reason they were thrilled when they got the chance to explore Wind Cave, one of the world's longest, with more than 53 miles of mapped passageways. (Call  745-4600.) Jewel Cave, also one of the world's longest, is known for its crystal formations. (Call  673-2288.)
There are wonderful ranger-led candlelight and spelunking tours available at Wind Cave, but because we had 2-year-old Melanie in tow, we opted for a more conventional tour that took us half a mile inside to see the world's best examples of boxwork, thin veins of calcite that crisscross the walls in a honeycomb pattern. The kids were especially impressed when the ranger turned out all the lights to give us a sense of what it had been like for the early cave explorers.
Early the next morning, we headed off on a different kind of adventure with retired Marine officer Joe Weston: a two-hour Jeep tour into the back country of Custer State Park. It was a bargain at $12 for the children and $15 for us (those under 3 are free). The Buffalo Jeep Safaris begin in May and run through September. (Call  255-4541.)