Warmest blanket
So we have a bunch of blankets that we use around the house. In the Runner I just have a couple large black bath towels mostly to throw on the leather seats for whatever occasion arises. My wife has a collection of quilts, those are hard to beat for holding it warmth. I used to get these wool military surplus blankets at a place up in Shelby, Ohio. They were $10-&15 ea. and various sizes. Have one that I keep by the recliner, I've had it for probably thirty years. It's the "go to" blanket for the cats since it holds heat so well. Go to a military surplus store or online surplus, get 3-4 for very little $ and get some large thick ziplocks to seal them in.