When returning from our final trip before winter, (we don't snowbird every year) I fill the gas tank,("regular" grade, as usual) then add an entire bottle of "Sta-bil". Start the motor, start the generator, and drive the 18 miles from the gas station to the house. That gives the "Sta-bil" time to get to everywhere in the fuel system including the generator. Easy.
Having no one to start the motorhome or the generator during the winter, I would suggest you remove the batteries. They might get damaged (or damage the motorhome battery trays)...and most likely would need replacement in the spring. Just my 2 cents.