RV Insurance / Liability Umbrella

With our insurance co. they require that all vehicles, houses etc. be covered by them with regular policies for umbrella coverage. Actually our umbrella policy is "almost" free, because with the umbrella, the liability coverage on each of my vehicles went down considerably with a much lower limit and the umbrella picks up the rest. But then we have 3 cars, 3 motorcycles, Two trailers, and one house. Basically, the liability on each vehicle is the state minimmum and the umbrella picks up the rest to the umbrella max. ($2M) Otherwise each of the vehicles would need much much higher liability for my protection of assets.