Here’s where you’ll find some of the nicest Little League baseball facilities in the San Francisco Bay Area including six baseball diamonds & an enclosed batting practice area. Sea Cloud Park also has some soccer fields and is a good place to start a bike ride along the San Francisco Bay Trail. http://www.fostercityfun.com/san-francisco-bay-trail-levee-pedway/#map
I bike this trail just about everyday. Great scenic views of the bay on all sports played on it such as sail boarding and kite boarding which are awesome to watch. Only bad thing is that there really no areas for off roading. Overall great for a relaxing walk/run/bike ride.
Bringing a mountain bike on this ride is like taking a Range Rover to the grocery store. It's all flat, paved, marked, etc. There is this one area south of the San Mateo Bridge and north of Oracle that is off the path. It's basically a little mountain bike trick course and it's pretty fun. Other than that, it's a road bike along the bay which means its flat and mostly windy.