My generator, a 8kw standby uses 1.35 gallons of LP per hour at full capacity. You may want to consider having a tank installed. Mine is 325 gallon. During a catastrophic event the gas company may shut off natural gas service; but you own your LP. The 10 circuits I back up are all I need in the event of an outage. This does not include hot water or my furnace.
But I do have a gas fireplace.
Do you want it your way or the right way?