If you can only stay for an hour or so, there is plenty to keep you busy in and around the Bear Valley Visitor Center. The visitor center itself contains several ecological and historical exhibits along with a seismograph, weather station, and auditorium for enjoying videos, slide shows, and other educational programs.
You might also like to visit Kule Loklo. A short path starting from the visitor center will lead you up to a replica of this Coast Miwok Indian Village. Interpretive signs briefly describe Coast Miwok culture, history, and the structures in the village. (1.3 km / 0.8 mi)
If a walk in the woods is more of what you're looking for then perhaps you'd enjoy a short hike on Woodpecker Trail. This beautiful loop trail explores local forest and meadows, with interpretive signs describing some plants and animals you may see along the way. (1.2 km / 0.7 mi)
For an introduction to local geological history there is the popular Earthquake Trail. This nearly flat trail is a short paved loop that explores the San Andreas Fault Zone. Interpretive signs describe the geology of the area. The trail entrance is located across the parking lot from the visitor center just to the left of the picnic area restrooms. (1.0 km / 0.6 miles)