We use all kinds of stuff depending on the season and where we are.
I frequently sleep in the GN of my trailer. If I brings my daughters, they usually set up a dome tent. I've got friends who just set up a cot out under the stairs. A cot gets you up off the ground and is easy to fold up and pack. In the colder weather we pack in a wall tent with a wood buring stove.
I've attened a Lot of CTR rides and witness people camping in anything imaginable. Swept out trailers, under the goosenecks, in tents, in back of Suburbans etc.