Our Jeep group from San Diego just explored the Calico area this past weekend. The Odessa Canyon Trail is much more difficult than the online articles indicated. It is not for the faint of heart.
If you are in orange country, check out the dirt devils meeting the first Tuesday of each month at 7pm. It is located at 2036 N Tustin, Orange. If not, there are local clubs all over California, You can also look up Cal4wheel club directory and there are a bunch in there