You have to be pretty inventive and a law breaker to find good tracks.
I once rode a Honda TL125 green sticker from my house on Fairman St. near Lakewood Country Club to the VW dealership on Cherry Ave, Long Beach. I utilized back alleys and the rail road, car parks and un-developed land around the airport. It helped my bike wasn't noisy and looked OK except no lights or plates. I also used to ride over to the Vets Stadium motorcycle swap meet on my Trials bike, same thing, back alleys, car parks, waste land.
Signal Hill used to be good. I haven't been there in 10 years. I suppose it's all either fenced or developed.
I don't know what the kids do now. My grand children ride around our yard on electric quads and Barbie Corvettes.