Cross country hikes are possible on lands that allow us to walk in any direction. Almost all the parks in the bay area disallow walking off trail because it destroys the trails and the surrounding eco-system. However, BLM lands are known for no such restrictions. Also, cross country hiking is possible in several parks near Lake Tahoe. Desolation Wilderness one such park.
Panoche, Griswold and Tumey Hills are BLM owned lands that allow cross-country hiking, which means that we may legally go off trails to explore. These lands are located about 2.5 hours east of San Jose. The landscape is unlike any other park in the bay area. Cross-country hiking is harder than regular hiking because the terrain is uneven. Plus good navigational skills in wilderness are important.
In April 2011, I joined a meetup group for an enjoyable 12-mile cross-country hike. The last few miles of the hike involved over 30 creek crossings, making it a unique and memorably experience. This hike can be done only in the month of April. Prior to April, water level is too high. May onwards, the temperature is too high.