This is a state beah and so during the summer months there is a parking fee, the trails start on the back end of the park near the pavilion, make sure you stay on marked trail and avoid the no riding signs in posted areas (mostly where the beach crowd is) once in you will find a 3.5-4 mile loop to explore, again during the summer there are a lot of people there so watch out for hikers, dogs, kids, etc... mostly single track and great ocean views
Take exit 72 off of I-95, follow off ramp to RT 156 and take a left, park entrance is 1/4 mile down on right
http://www.singletracks.com/item.php?c=1&i=7151