The Ohlone Wilderness Trail out of Lake Del Valle is NO joke. It took us 8 hrs to get to Doe Canyon horse camp, just past Rose Peak, where we spent the night. The next day, it only took 5 hours to get back. Much of the trail is very steep.
Absolutely worth the effort – the views of the Bay Area from the top of the world were spectacular. And it felt like we were in the middle of nowhere sometimes..yet so close to civilization.