Without a blanket because the wind blew it away

If you get a big enough campervan you can put a nice big heavy mattress in it.

shit I have a pair of inflatable twin mattresses that can be joined together. open up my sleeping bag, put it down as base warmth, with a pillow and another cozy blanket… That pretty much meets the definition

Nobody says you can’t 🤷🏻‍♂️

My parents had a bed built for their minivan with ample storage and a thick layer of latex foam. They did some trips around the US using that, though ultimately it turns out they’re just not great sleepers.