We have our sleeping situation set up so that our little guy sleeps on the floor of the truck on a crib mattress that we had made him out of a piece of memory foam. It is very comfortable and weighs very little so it is easy to move around. The mattress lies lengthwise down the center of the truck between the two chairs. Unfortunately, with the mattress being so thin it is absorbing a lot of the cold that is coming up from the floor making it more solid. I have spent several weeks now trying to find the best solution to the problem. Here's what I have done so far:
- Wrap the mattress in a thick woolen blanket;
- Surround the edge of the mattress next to the driver chairs with pillows to block any wind leak in the through the door edges;
- Cover the little guy up with two blankets;
- Dressed him in fleece winter pajamas and socks.
I have also seriously considered an electric blanket and you may wish to do so too.