We took the metal cage that our 6 month old Cockapoo sleeps in at home, & he slept in the awning quite happily. We draped a fleece blanket over it at night to cut down the light & make it a bit warmer. One night was quite cold, (5c or maybe less), so he went in one of the fold-up fabric crates at the kids end of the van. Again, no issues & he was no trouble trying to get out etc. As soon as he came out the cage in the morning though its time to zip yourself into the sleeping bags as anything poking out is fair game.

He also spent an afternoon in the fabric crate inside the van, as we took the children to an adventure park that wouldn't take dogs. We still had neighbours when we came back so he must have behaved himself & not howled the place down.
The fabric crate is brilliant, it folds totally flat in seconds & is easily stored in the wardrobe or under the bed. It has roll up windows & a mesh door. Its made from some seriously tough fabric, it would take a heck of a beating from a ravenous puppy. Its made by Lazy Bones.