Generator use

Assuming you have a 4.0KW Onan gas generator, you can expect to use at a minimum 0.5 gallons per hour running one ac in your class C. This is the generally accepted consumption.

I have an 80 gallon tank so I could probably be okay for the entire time, your rig on the other hand may need refueling either by pump or by manual can transfer.

More information would have gotten more and better answers.

What generator do you have? I would hesitate to subject a cheap HF unit to that kind of use. Other than going through a lot of fuel you should be alright although you may get tired of listening to it. Change the oil before you go and check the level each time you refill the tank or every five hours or so. DO NOT refuel with the unit running.

That's not a problem at all so far as the generator is concerned. Stopping and letting it cool down and restarting it cold would be harder on it than letting it run. It's not going to be any hotter after ten hours than after one or two.

You'll probably have to purchase gasoline at least once and possibly twice for that length of runtime, or obviously more frequently if traveling. If perchance it's a propane generator, you'll need propane several times. The generator should be shut down while refueling, just as for the main engine; that is legally required in most if not all states, besides just being good common sense. It would not hurt to check the oil level and add some if needed at the same time.