Actually, may not be simple. There is more than one answer to your question depending on your coach, inverter, generator, etc. For example, on mine I need to have the inverter on for there to be power to the inverter supplied circuits even if I am on shore or generator power. If your inverter also charges your house battery's you may need it on to accomplish that function.
Best bet is to whip out the 'ol manuals and read up on it.
2005 Beaver Monterey Laguna IV
C9 400hp Allison Xantrex RS2000 Onan Aqua Hot CRV