Efficiency aside, I would think having a genset using the same fuel as your engine is far more easy to deal with as MM indicated. One fuel, one stop, pump yourself and a lot more of it. You'd have to have a prety large LP tank to compete with the size of the fuel tank on the MH. I have a whole house LP generator on the sticks and bricks and it runs fine. But it's hooked to a 500 gal tank. I chose not to have diesel in that application because it would be a pain to fill myself and the length of time the fuel would sit un-used. So that application is the total inverse of a MH where you can share the fuel and it does not sit. I am with MM, go with what's easier.