Nearly every Sunday the San Mateo park rangers block off most of Cañada Road in the hills of Belmont to safely ride your bike, scooter, skates, go for a run, or just have a nice walk. With just over 4 miles set aside, the rangers set up a road block just south of 92 and just north of the turn off for Filoli. http://parks.smcgov.org/bicycle-sunday
There is usually abundant parking on either end, we have been parking on Edgewood Road by the intersection of Cañada Road and riding our bikes along the shoulder till we pass the turnoff for Filoli were the rangers roadblock is, and continue on. There is some traffic along that stretch but the road is wide enough and there is a decent shoulder to ride in.
There is an overall 500 foot elevation gain, and there are some hills, but really it's not too bad (you can always hop off and walk your bike). The biggest hill is in mile at the northern end of the route. We have had more success starting from the southern end because trying to tackle this hill at the end of a ride can be a little taxing on my kids.
It seems like the rangers have set up a little water/bike pump station at the northern end too, and the kids get a kick out of chatting with the rangers (who I guess get a bit bored standing around there all day).
Picnic at the Water Temple
if you haven't visited the site before, the Pulgas Water Temple is breathtaking. It's open all week and on Saturdays there tends to be a number of weddings booked. Sunday however is a great day to visit as you cannot access it by car.
The site is one of the last links in the chain for out water system. The water stored in Hetch Hetchy is piped down to Sonol in the East Bay to a very similar Water Temple where the water goes underground into a pipe that crosses under the bay. The water is then released at the Pulgas Water Temple site to flow into Crystal Springs, that giant reservoir you see just west of highway 280. Until renovations a few years back, you could hear the deafening roar of water at the sub-terranean reflecting pool. Now just a casual amount of water flows through as the water has been rerouted.
The grounds are meticulously kept, and it's a great spot to throw down a blanket in the shade or let the kids roll down the grassy hills. There is a water fountain here and port-a-potties if the need arises. Be sure to walk your bike around the property. This is a great spot for pictures.