To Hiddenbrooke Summit (2.3 miles): Walk 0.5 miles along a bike trail that parallels Hiddenbrooke Parkway to reach the park entrance for Hiddenbrooke Open Space Preserve on the right. Enter the preserve and follow Hiddenbrooke Trail for 0.9 miles to reach a sign that asks you to turn left instead of continuing along an unmaintained trail straight ahead. After 0.3 miles, you reach a junction. Turn right at the junction. Walk 0.3 miles to reach a junction with Summit Trail. Turn right onto Summit Trail, walk 0.3 miles to the summit.
To McGary Road Parking Lot (2.3 miles): Retrace your steps back to the parking lot on McGary Road.
Along I-80 East, take exit 36 for American Canyon Road. Turn right at the exit, then take an immediate right onto McGary Road. There is space for parking several cars on the right (zoom into Google Maps to see its location).