A family of five can rest comfortably inside a camper trailer for example from a company like GIC Campers (you can see some examples of packages athttp://giccampertrailers.com.au/camper-trailer-packages/), especially if you have kids which are young enough to share the same bed with you. Basic camping trailers have two fold outs onboard which are utilized as sleeping quarters. For the main part you will have a small dining area, cooking area which includes a small refrigerator and a storage area. Oftentimes, there will also be a grilling area and outdoor shower.
You might have noticed that there is no toilet that is mentioned. That is because a low-end camper trailers normally does not have one onboard. A lot of people make use of portable toilets or camp ground facilities in case of an emergency.