We love this park. It has all the elements to make it perfect for everyone - a baby playground (enclosed by a fence that has a gate that kids can't open), a well-shaded playground for bigger kids, a shaded sand area, grassy hills with sufficient shade for great picnics, and a water area where water shoots up somewhat randomly. Our 4 year old thinks the water area is awesome while our 1.5 year old loves the twisty slide in the bigger playground.
The best thing about the layout of the park is that if you are watching multiple kids who are interested in playing in different areas, you can situate yourself on top of a hill and see many parts of the park at once.
And, it has a couple bathrooms -- that have always been clean every time we've needed to use it.
(While we've gone to this park a lot, we most recently went on a 90 degree day - can't you tell?)
Burton Park in San Carlos is awesome! It has been completely remodeled and is very well maintained. There are two playgrounds- a large structure/ swing area for older kids (4 and up), and an adorable, fenced tot area with lots of shade, brand new Trex picnic tables, and bathrooms just steps away. The tot area has a climbing/slide structure, baby swings, lovely grass lawn for picnics, and as I mentioned, it is totally fenced and gated and safe!!!
Parking is a breeze- there is a small lot adjacent to the playground, as well as plentiful street parking. Bring a lunch (or stop in at one of the many food joints on Laurel Ave). Its so relaxing to be able to let your little ones run around without worrying about them wandering into the street.