Diablo Trails Explorer Fitness Hike at Brown’s Ranch Trailhead. This Very Difficult hike will head to the North and South Diablo trails. There will be stops at Cathedral Rock and the Amphitheater along the way. Experienced hikers suggested.  About 5 hours to cover 10.5 miles on rolling terrain.  Bathrooms are available at the trailhead.. Bring water, snacks and even a lunch for the trail. No dogs please.  Arrive 15 minutes before start of hike.