My 12-year-old daughter stands on the boardwalk at Yellowstone's West Thumb Geyser Basin, aiming a borrowed digital laser thermometer at the hot pools and mud pots simmering nearby. She clicks the trigger and reads the display: 120 degrees … 155 degrees … even 170 degrees.

Close by, another girl snaps a photo of Fishing Cone, where early Yellowstone visitors used to cook their fish straight from Yellowstone Lake. Each of the five children in our group, ages 8 to 13, received a digital camera the first night to use during their stay. Our leader Jen Rudolph – a middle school teacher from Massachusetts - reminds us how Thomas Moran's artwork and William Henry Jackson's photographs helped sell Congress on the idea of Yellowstone as the world's first national park. She promises to develop the kids' favorite photos at the end of the trip, and adds this challenge: "I want you to think about which of your photos could someday help save Yellowstone."

For four days, we three families learn, hike, play and eat picnic lunches together, separating only for nights spent in comfortable digs at the Grant Village. We walk carefully past a buffalo wallowing along the trail to Storm Point, we see sandhill cranes dance at sunset in Hayden Valley, and we use watercolors to capture the summer glow at the Grand Canyon of the Yellowstone.

Most families visiting Yellowstone tend to blow through the park in a day or two, rarely traveling far from their vehicles and seldom getting a behind-the-scenes look at the park's geology, wildlife or history. But after many summers of exploring Yellowstone, Jen knows the park like a second home. When we reach Old Faithful, she spontaneously hails us past the famous geyser to see an unexpected matinee performance by Beehive Geyser – a less-regular but spectacular feature in the same vicinity. We still catch Old Faithful, too, but from a backside vantage point far from the boardwalk crowds.