China Flat Trail can be reached off Lindero Canyon Road in Oak Park, between King James Court and Wembly Avenue. The trail sits below Simi Peak, at 2,405 feet, the tallest peak in the Simi Hills.
My kids particularly enjoy exploring the sandstone caves pictured above and below. Beautiful views abound hiking up here. It does get a little rocky and steep at times so just be aware. It is about two miles to the top, making it about a 4 mile hike. Hike another .8 mile to Simi Peak.