Do you have a generator? And will they let you use it?
If so, don't drive until you need to get more gas. Run your generator to charge your batteries and power your 120vac appliances.
Do you know if you have 1 battery or 2? If you have just one battery you're not going to like the time you can run on battery. It's probably just an hour or 2 depending on what you run.
Do you know if you even have an inverter for your coach? That would power your 120vac appliances....but not for long.
Need more information on what you have.