Mike, I'm just south of Sacramento in the Lodi area. I love living over here, just like you said tons of great places to ride here. I've been riding solo for the most part, most of my friends ride MX(non street legal bikes) or quads. lol I've been trying to convert them and I think I've been successful to a degree, but none of them have the financial means for getting a dual sport or enduro bike.
I have a buddy that rides a street legal CR500, bad ass bike, and we're always down to ride.
To name a few places I like to ride, Ione(closest, largest and cheapest place to me, FREE), Prairie City(ok place to ride, about 5 bucks to get in, but I have several friend that work the entrence and sometimes get in for free.), Forest Hill(Bad ass place to ride, free, just a little far for me) and there are just tons of places to ride dual sports and enduros all over the mountains here, up I80/HWY88/HWY50/HWY108.
I really want to make some trips to Hollister and Carnegie, both are south from here, up north I've been to Cow Mountain and Knoxville(both really large and cool places to ride).
I'll shoot you over a PM with my number and facebook link, hit me up anytime, I'm always trying to find people to go ride with.