Hi Greg,
Good to hear from you and glad you're still riding.
I lived in that area for 22 years. I've parked at the bridge and never had a problem but I understand how you might not want to. You can park at the strip mall, just beyond the YMCA. We once had someone attempt to break into our car late at night when we were at the theatres next door but we parked along the backside of the building, not in front of the theatre. That was before the Y was built.
Mt. San Miguel is a nice 3.5 mile ride, it gets steeper at the top. There was one gate that you had to sneak around (many years ago, the last time I rode). From the bridge there are also some very good mountain biking trails that head west along the Sweetwater River.
Enjoy,
Tom Reynolds