Thinking of a class A but have one question about the gen

Well I guess is just like my travel trailer, I only run one unless I need the AC so I guess the same would apply to the class A. I just like the convenience of having everything built in and not having to go outside and hook anything up so I never thought in those terms. It was a convenience issue for me not a fuel issue but I guess I won’t really know just how much fuel it burns until I actually purchase one and I could change my mind rapidly :)