Ballinger Canyon Road intersects with Highway 33, approx. 40 miles north of Ojai. It is about 3 miles south of the intersection of Hwy 33 and Hwy 166, so if you hit 166 you have gone too far north.
From northbound 33, turn right on Ballinger Canyon Road. The staging area is about 2.5 miles off of Hwy 33. There are some restrooms, but no RV hook-ups. Definitely try to pick up a map before you go - there may be maps on a billboard at the staging area, but don't count on it.
Word of warning - when cresting the blind hills, slow down! Some drop steeply as they roller coaster up and won. As with other USFS riding areas, many of the best trails are the ones that are farthest from the staging areas.
http://www.employees.org/~calridng/allsites.html this link has a map and contact info for many riding areas. You can find Ballinger Canyon and ranger contact info at the link.