Thanks for the pointer on avoiding "wicking" of moisture into the interior. The sun melted some of the snow off the F150 windshield, but left a very heavy layer of ice over the driver's side. Even the spray on deice liquid isn't touching it this evening. We're on the way down to -6 F. The sun just set, so temps will be dropping quickly.
The blanket should do a fair job at your present temperatures. I find that only a few people try this even though it works. Maybe it isn’t stylish.