I start camping in California back in 1987 and those rules more or less applied then. Only difference I remember from those years was that some campgrounds would allow gray water damping.
That said, with RV you have lot of choices.
My favorite over the years was Crystal Basin area, who belongs to Sacramento Water District. 7 different lakes past Pollock Pines few miles you turn left into Ice House Road. Some mountain driving and it is your choice of lake size and elevation (temp changes). Still can find beach campgrounds with no fees.
Being self-employed most of those years, during school vacations I would go there on Sunday and go home on Friday before ZOO started at the lakes.