Broke Posted Order in California State Park

My question involves criminal law for the state of: California.

Greetings all, and thanks for this very helpful website.

A few months ago I entered the property of a California State Park after it was already closed for the evening. I drove up past the designated parking lot for visitors onto the road(s) that were supposed to be for State vehicles only, or something about like that as far as I know.

No one was around, so I drove under the very rickety guard gate/barrier and back into the State Park property. There were a few signs with vague notices that said something like "no public access" or something like that, but not any official codes/state laws/etc were posted as I remember.

Anyway, a while later, somewhere deeper into the State Park, a park ranger came and found me (I was outside of my parked car, just checking out the scenery - nothing sketchy), and issued me a Notice To Appear ticket for a Misdemeanor for breaking a Posted Order (the exact violation is linked below). I was then escorted off the State Park by another ranger after I stupidly apologized to them for being inappropriate or something general like that.

I have pasted the California Code that I was cited for at this temporary link:
http://pastebin.com/m69a43c6a

(Please don't mention the violation code details or anything in this post. I'm paranoid.)

I have some questions for anyone who can help me:

1) Is this violation technically "trespassing"? Or what? If so, how bad is it?
2) What types of punishment can I expect for this? This is my first MSDMNR or criminal charge, for that matter
3) Will my vague apology to the rangers hurt my case? (Should I plead Not Guilty no matter what?...)
4) Should I hire an attorney? I've read many posts on this forum that say a lawyer might be able to negotiate with the DA before my court appearance date to get things like a "pay fine only" settlement, deferral, or even complete dismissal.

If anyone can explain to me my most likely options here, or anything else that might be helpful that I'm not realizing, I would very much appreciate it. Thank you for your time.

You've stated that you're charged with a misdemeanor (a crime) so it makes sense to talk to a lawyer about how to proceed. You may be able to get the charge reduced or even dismissed. If you're convicted, absent a record you haven't told us about, realistically speaking I wouldn't expect much more than a fine - but a misdemeanor conviction would result in a criminal record.