Speaking from experience:

You’ll contend with noises and lights all night.

You’ll need a winter rated sleeping bag, ideally a mummy bag.

You need to lay flat. You cannot get a good nights sleep reclining in a seat. You need a van, not a sedan.

Even so, you’ll probably wake up in the middle of the night with cold air on your face. A knit hood helps a lot.

Even so, I can’t imagine doing this more than one night.