Important! Every time we go we wish we had some kind of water shoes. They can be shoes that market themselves as "water shoes" or just shoes you don't mind wearing in the water. But the rocks are uncomfortable on the feets. I'm very good at packing things like this for my kids, but then forgetting to do it for myself. So bring water shoes for the grown-ups, too. (John, help me remember please).
More about how this works can be found here. Directions are below. More about Sunol is here. Weather forecast is beautiful. It's spring. Let's go!
Directions to Sunol
Drive east on I-580 to the junction with I-680 in Pleasanton. At the junction, go south on I-680 and exit at Calaveras Road/Highway 84 just south of the town of Pleasanton. Turn left onto Calaveras Road and proceed to Geary Road, which leads directly into the park. After the kiosk (bring $5!) turn left towards the Old Green Barn Visitor Center. There's also parking straight ahead.