[SargeW]

My last RV was a 40' diesel pusher, all electric. It had an on board 10,000 watt Onan that easily ran the whole RV, including 3 15,000 roof AC units. The key to success was a good on board energy management system (EMS) that would move loads, or turn them off and on as needed.

The point of the story is that you can do the same with a smaller generator, as long as you act as the EMS. Because the reality is that how often are you going to try to power every appliance in the rig at one time? Not often. A smaller sized capable generator will most likely serve you fine, with a little common sense.