Bonelli Regional Park is an almost 2000 acre Los Angeles County facility surrounding Puddingstone Reservour in San Dimas. Triathlons and many other events are held there during the year. The park is open from sunrise to 7 PM in the winter and 9 PM in the summer. To drive in, the entry fee is $10 per vehicle. But if you just want to bike or run the trails, many use the Park N' Ride lot on Via Verde and enter on foot at no cost. Drinking fountains and bathrooms are all around the park, but best to take a water bottle in the hot months. Just on the other side of the 57 freeway from the NW corner of Bonelli Park is the Antonovich Trail head which follows the stream down through Walnut Creek Park - another good single track trail as an alternative. After the run, Norm's Hanger Restaurant in the terminal building on the south side of Brackett Field is a good place to eat and watch the airplanes.