May I make a suggestion?
When you are looking at the fuel use of the generators, many manufacturers list it XX hours at XX gallons. What they often do not mention is that those figures are for operating at 50% of running watts.
When I sized for my bus, I added up what I wanted to operate. Upped the starting watts for all the compressors (I doubled running watts to get my compressor start ups). I only figured one AC unit since I would only run AC in the bedroom overnight. Then I doubled all that. That's how I came up with the running watts I needed.
Another thing you have to be very careful about, or ignore it completely, is the decibel ratings. Seems like no two manufacturers use the same distance. I have a cheap open frame contractor LP generator. I can stand at the from of my 40 ft bus and I can carry on a normal conversation with the generator running at the rear of the bus. For that my suggestion is to find youtube videos and listen to the generators.
Since I operate my generator in parking lots, normally next to a semi-truck that is idling all night long, I don't really care a whole lot about the decibel rating.