If you precondition before unplugging helps a lot. Not much different than letting an ice get to operating temp before driving it.
You could also put a diesel heater in the bed and duct it into the car. You'll be real warm then.
The only time I've used a radio in the last 10 years was when I'm driving the farm truck to get feed and that's because that's all it has. And the reception is terrible from interference.
I think this is very good info if you plan on this being your only vehicle. If you have a second car in the household you can use that instead.
This does get away from the "everyone has their car and no one drives mine" idea that's prevalent in the US.
But that mindset is not very practical or...
Several articles and videos have been posted on here about how extra weight doesn't effect range very much. However, it would definitely hurt 0-60.
Of your other power draw comparisons the heater and AC would probably be the only noticable changes in range.