Get a good workout and explore the history of the hills east of Hayward at Garin-Dry Creek Pioneer Regional Park. Ancient traditions and recent tragedies form the backdrop for this 10-mile hike at Garin-Dry Creek Pioneer Regional Park in the hills east of Hayward, California. The tradition: mortar holes the Ohlone peoples used to grind acorns into flour near Gossip Rock, a loop/spur from the park's High Ridge Loop Trail. The tragedy: a 1951 airliner crash that killed 50 people when the plane smashed into Tolman Peak. While no wreckage is visible from the trail, it's haunting enough to know so much was lost on this hilltop. The route also provides impressive views of the San Francisco Bay and the nearby East Bay Hills; expect to see raptors, deer and the occasional coyote. Trails on this route: High Ridge Loop Trail, Spur to Gossip Rock loop, Tolman Peak Trail, South Fork Trail, High Ridge Loop Trail. Skip the Tolman Peak section to slice three miles from the hike. The peaks on this route are not especially high, but the combined ascent is considerable: over 3,000 feet when all the hiking's done. Best times to go: Early to late spring, when the hills green up and the wildflowers put on their annual show. Winter is fine, too, though bear in mind the trails get very muddy. Give them a few days to dry out after a passing storm system blows through. Summer's too hot, but cooler weather in the autumn make the hiking pleasant.