We saw the full range of camping rigs when we were away, the biggest was a caravan being used by a member of Infamous Cabaret Circus, I think. The show was in Darwin when we were there, later we saw the rig on the road.
Fifth Wheelers are also BIG, they comprise a ute with a fitting in the tray that connects to a long caravan.
There are some very big Motorhomes, some have expandable sides so that when they’re set up the “room” inside expands. Unimogs are big and so are other similar setups. Buses come in a range of sizes.
Many of the caravans we saw I would have considered big until I saw those gigantic ones. The caravan in this set is like our family caravan of the 1950s and I’m one of five children! Maybe the “big boys” slept outside.
A lot of clever ideas have gone into designing compact campers, we have a kitchen with sink, burners, draining board and storage all on the outside of ours.
No matter what size the camper, caravan, campervan or bus is, “stuff” will fill the space.
People with the smallest “accommodation” must be a lot better than we are at prioritising their needs.