no 'large' coach will have sufficient chassis heat when driving in very frigid temps - we plug in a 750w electric heater between the front seats - the inverter may can handle it while the alternator provides charging, but the AGS for the generator can also be set to come on when the volts drop too low(battery levels) to keep the heater running...
yes, run the propane furnace
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
110,000+mi since '14 - US, Alaska, Canada (also, '14 Gulfstream Amerilite and '07 ForestRiver Rockwood) : )b