The Clark trailhead is not so bad after all. There are about four parking spaces at the end of Clark Rd by a Waldorf school. There will be no shade for a while, no bathrooms and no water. There are places to paint as soon as you enter the park.
Directions: From 80, take the San Pablo Dam Rd past El Portal, Appian/La Colina, and Milton Dr. The next entrance to your right is Clark Rd. If you live in Berkeley, you can also take Wildcat Canyon Rd to San Pablo Dam Rd and make a left on Clark Rd.