I spent the last several years going to Ventura County, CA several times a year though, and saw all of what Ben has described there. Trash on the side of the road, shitty ghetto areas with Spanish graffiti, obvious Latin gangs on the streets, the whole bit.
And that was just on base.
I think you spent your time at Hueneme and not Mugu? The Hueneme area is probably one of the worst areas in VC for all you described above, so you were certainly in the thick of it.
I agree on the "regionalization" (because I think we have a much, much larger illegal population than any of the official numbers state). When I talk about "speaking Mexican in the Costco", I should elaborate that I see two different kinds of speaking Spanish. Here, it's just people speaking Spanish with each other*. In CA, it felt to me like it was people speaking "entitled Spanish". "I'll speak Spanish, I'll make sure you notice, and oh yeah - in your face, because we're in charge around here!"
* Which I don't mind much, though when I was growing up, it was considered to be extremely rude by all the immigrants my family hung out with to speak German out in public. Sure, it was fine when meeting with other German families at the park for a BBQ or whatever, but in a store or the bank or what have you while interacting with people that don't speak German? Speak English.