Convenience and Efficiency Have some relationship. running on propane, you will eventually have to refill the tank, running on the inverter with a DP, I am sure you will never notice a milage difference in fuel consumption. Because the ref. uses quite a few amps on 120v I switch to gas when parked and not connected to exterior power. There were a few recalls on dual fuel refrigerators in the past because of a fire hazard. I think the industry has eliminated that problem.
Back to your original post: I feel like the most complicated system in a rv is connecting up at a park, filling the water tank, and having all the valves switched correctly for what you're trying to do
that being said, I would concentrate on the water system.
That assumes you know how to drive that big thing already.
