Even a Great Dane will feel dwarfed on a hike featuring the giants of Marin County’s San Geronimo Valley. The 300-acre Roy's Redwoods Open Space Preserve, under jurisdiction of Marin County Parks & Open Space, is doubly rewarding in spring, when the meadow at the trailhead is splashed with wildflowers that paint a colorful swash against the somber palette of “big boys” in the distance. Rover will have to stay leashed as you explore the web of trails leading to and through the grove, but there are so many interesting plants (and other visiting canines) to sniff that he won’t mind. Read more.