Assuming that the display is going to be bigger than 15 inches, the TV will be drawing some power. I just looked up 1 TV and it showed 170 watts. 170 watts with 50 percent inverter efficiency at 12V is about 28 amps. I'm going to take a guess that the car's 12V battery may only have about 30amp-hours, which means the car will die pretty quickly.
That not sounding good, I looked up the cheapest, smallest Vizio TV and it was only 18 watts, so that's about 3 amps. I'd be guess that I'd want to run for less than 5 hours. It may be easiest (and represent a better disaster proof position on your point) to go get a small, very quiet generator, like a Honda.
Oh, and last weekend, my Model 3 used about 40 miles of charger being displayed for 4 hours. The car rarely got to sleep and the AC was going at full blast with the windows down. After being in the sun for a couple of hours, I started sitting in the car doing demos a lot more.
Oh, and I believe to keep the accessory outlet own, you will have to keep the car from going to sleep.
You've always want an excuse for buying a little generator....Just get a quiet one.