I was lucky to have propane heat. Though I had no electricity to make the central heat come on, I was able to run the stovetop burners. It never got below 50 in the house.
Good plan. 50° is more than survivable.
When the power went out here in Michigan during an ice storm we opened up the vents in the basement and set the kerosene heaters below them, shut off unnecessary vents andhung blankets in doorways. It worked long enough.