For purposes of photographic dilettantism.

Any rough looking industrial area will also do.
I don't have anything spectacular in mind, just a hobby shoot.

I find it difficult to just go and photograph industrial locations, it seems in CA one gets challenged by security personnel for just about anything.

Basically, I just don't wanna get arrested, mugged or killed for trying to have some fun with my camera.

I don't expect anything like this

but anything that comes close would do.

There is the abandoned train station in emeryville/oakland. Maybe someone here can give an actual location. It's pretty low key

There is the bunkers in Marin Headlands, Presidio, and Fort Funston.
The working nike missile silo in Marin Headlands they lower you down with the missile - http://www.nps.gov/goga/nike-missile-site.htm
Hunters Point Shipyard - heard it used to be easy, bad area though. http://www.flickr.com/photos/telstar/sets/56935/

Oh and I agree everything has security. Being from NY I used to just walk into abandoned Insane asylums, Factories, Train scrap yards.