What a cool discovery! You leave Route 160 just a little north of the bridge that takes you to Pittsburg/ Antioch and take a bumpy little road along the edge of Sherman Island. The road follows the southern side of the Sacramento River to the tip of the island, where there is a nice county park for the windsurfers. It's roughly where the Sac River meets the San Joaquin River, and it is a great windsurfing spot.
Close to Lone Pine, really excellent view of Owens Valley south over dry Owens Lake, The last 2 miles have many brutal diagonal speed bumps, beware!