By the way, the wife and I have talked about this regularly over the years, so I actually went and looked at our panel to see what would be reasonable (again to be verified by a professional). Our house runs on all electric. HVAC, etc. All of it, due to the design of the subdivision in the mid-90s.
We’ve got a 200 amp feed from the utility which can be completely disconnected with a simple main disconnect breaker at the top of the box.
Adding a “campground” style 30 amp plug to the side of the house and running it to the box would probably cost me $300-500 (my next door neighbor is a plumber who’s drilled a number of holes in our basement walls already and the cable would only need to go about 15-20 feet). Then I (or someone qualified) would just have to add another 30 amp breaker to the box, connect it to the appropriate 15 amp circuits, and then hook up some kind of as yet to be determined failsafe that would never allow the utility power and generator power to be connected at the same time.
30 amp, 120 volt power delivers 3600 watts which is what the Costco generator delivers. Now the full electric HVAC is 60/60 ampacity at 220 volts which is about 26,000 watts and the biggest draw in the house so the HVAC and the stove and a couple other things couldn’t be run, but small space heaters and blankets could make that survivable. And a wood stove in the basement that we’ve talked about could really make it toasty (and keep the water pipes from freezing).
Now maybe if you’ve got natural gas, propane, or oil heat you may be able to run the whole thing with one of the larger generators.
Again, that’s how I’d do it.