An old understanding
In feudal times more often than not kingdoms had armies on the march. An army cannot survive with just warriors though, they need camper trailers. In this context camper trailers were the support staff of an army on the move. It was the cooks, Fletcher’s washer women, hookers and whores, hunters and scavengers. The got the name camper trailers because as the army marched they trailed behind. Camper trailers allowed the mobile army to eat and have their weapons repaired. They gave the warriors the comfort of women and even clean clothes. Even the medical staff fell under the name of camper trailers. Of course in these modern time the term has a much different meaning.