imo a back up generator big enough to power a home 100 percent should be a diesel.A regular portable like a honda eu series or any similar should be gas.dual fuel does no good in this situation.This is why gasoline Hondas are superior.
Easy to keep a few gallons of gas for up to 6 months without a worry.3-4 5 gallon cans dump in car say 5 months refill them with fresh