I am working on this problem also. Generator will be propane fueled. Remote
switch for starting..Will add outlets near freezer, refrigerator and heat
system. These will only be connected to the generator. Safe and easy to move
plugs from one outlet to others.

You will need a lot of propane, far more than 1 or 2 gas grill 20
pound tanks.

buy the smallest generator you can get away with, because big
generators use lots of fuel even at idle