If you have gas in the house, you might want to look into a gas fireplace or another backup heat source. We did this in our previous home, and it helped a lot during power outages.
You can use a camp stove as long as you’re not in a tiny room. If you need to cook for a while, move it to a different area and crack a window. Having a CO monitor is a good idea.
Yes, sometimes you do have to go outside to cook when the power’s out. I use my outdoor grill to cook during outages, sometimes with propane, sometimes with charcoal.
What about a small gas-powered generator? I have a small Yamaha that runs my furnace and freezer. It can’t run an electric stove, but it can power an electric kettle and charge phones.
I’ve been warned not to use camping stoves indoors because they’re not built for it. People have died using stoves without proper ventilation, so I wouldn’t recommend it.