Cold weather tailgating

Hi all. As you may know I'm a new owner of a 2014.5 lounge ext. I'm going to practice tailgate today at our neighborhood Turkeybowl gathering. Temperature is a balmy 28 rising to 40. I'll be running the furnace a bit to provide a "warming hut". Do I need to run the generator or just keep an eye on battery level. And at what point should I crank up the generator?



Thanks in advance for this community of users



SB