When you get to the lake the best place to park is in the boat launch area. After you enter the park go to the bottom of the hill and turn right onto Angels Creek Access Road and follow it around to the large parking lot. There is a nice large paved lot and full use bathrooms including sinks with running water. As far as I know there is no potable water at any of the trailheads here but there are plenty of places to get water in nearby Angels Camp.
The quickest access to Singletrack is by using the paved service road at the entrance to the boat launch parking lot (It goes to the Water treatment plant on the map). I usually turn left to take the Angels Creek loop in a clockwise fashion and then take the Buckbrush loop, then go up the Frontier Trail as an out and back that gives me about 9 miles of riding. For more miles and climbing add the Carson Creek Trail and the Tower Climb.