Here's the furthest upstream of the San Lorenzo River series, at least for this season: starting from park HQ, we'll take the trail to Cable Car Beach, then follow the river downstream to the Garden of Eden, returning along the railroad tracks. The river route can be done mostly rock-hopping along the shore, with the occasional crossing, in which case you'll get wet up to your knees. It can also be done mostly in the water, in which case you'll get completely soaked (but will have a chance to dry off on the walk back). Whichever way you choose, amphibious footwear with good traction is called for; the leader will be in hiking sandals (as usual), but sneakers (that you don't mind getting wet) can work too. Total distance is about 5 miles, of which, depending on individual preferences, anywhere between 100 feet and 1 mile can be in the water. Bring water, lunch, carpool/parking money, and a sense of adventure. Meet at carpool point #8.
Directions to LPSS carpool point #8 (Homestead Square in Cupertino): Exit 280 onto Saratoga-Sunnyvale Rd (De Anza Blvd) towards Sunnyvale (north). First left on Homestead. Shopping center is on left side. Pass RiteAid and the PW Market, and continue to the north end of the shopping center. Park along the Homestead side, near Carl's Jr.