We did put in extra cord wood just before the cold snap [thanks to local woodman Ted!], and that has provided peace of mind. We also called up the propane company last Thursday to ensure we were still a customer [ha!].
The kind gal there offered to send the truck that day, a week early by her reckoning. The driver reported we would never have made it another week. So crisis averted, lesson learned, and happily we drift into a week of warmer weather. Whew.