Sarge,
The East Bay Regional Parks Police have a web site for non-emergency incident reporting at
http://www.ebparks.org/Police/pwr.htm. Among ordinances adopted, there is
908.8 General Noise Regulations.
a). General. Notwithstanding any other provision of this Chapter, and in addition thereto, it shall be unlawful for any person to willfully make or continue, or cause to be made or continued, any loud, unnecessary or unusual noise which disturbs the peace or quiet within any area within the District or which causes discomfort or annoyance to any reasonable person of normal sensitiveness utilizing any facility of the District.
b). Standards. The standards which shall be considered in determining whether a violation of the provisions of this Section exists shall include but not be limited to, the following
1). The level of the noise
2). The intensity of the noise
3). Whether the nature of the noise is usual or unusual
4). The level and intensity of the background noise, if any
5). The type of area within which the noise emanates
6). The intensity of human use of the area during the time at which the noise emanates
7). The time of the day or night the noise occurs
8 ). The duration of the noise
9). Whether the noise is recurrent, intermittent, or constant.
While there might be little satisfaction in reporting anything after the fact, doing so can at least emphasize to authorities that a problem exists.
In practice, I have found that urban proximity tends to attract dirtbags. Locations between 30 - 45 minutes of any concentrated urban area seem to attract some pretty rude people. Especially when there is mixed day-use and camping. Somewhere around 1.5 to 2 hours away things tend to thin out and appreciation for the environment and consideration increases (there are exceptions, though). Talking up experiences and plans with co-workers, neighbors, friends and acquaintances can sometimes give a heads-up on what to expect.
I realize that with Little Sarge along and Mom biding her time at home, you might want to stay closer. Sorry about your experience.
Tom
A neighbor of mine has an electric pocket bike that he rides though the local park at night without a light. I've thought of getting a laser pointer to see what he thinks of that on his chest , or in the middle of his forehead. 
How 'bout a tack strip? Then again, you might try talking to them, but then again, that would not be nearly amusing. 
