I can recommend the Sycamore Canyon campground about 5 miles south of Pt. Magu, north of Malibu as a nice place to spend the night. There aren't any stores around there, so you have to bring food but there are showers and a hiker/biker site. Though, you have to check and see if it is still open given California budget problems.

View from my tent at Sycamore Canyon:



Ray