Auto-Kamp Equipment Co.
The Auto-Kamp trailer was among the first manufacturers and is very well known. They were manufactured in Saginaw, Michigan. One source shows them in business from 1914 until 1930. According to May 17,1916 Motor magazine
"the Auto Kamp Equipment Co., organized with a capital stock of $15,000. Automobiles, trailers, and other vehicles and appliances will be bought, sold and manufactured. The incorporators are C. W. McClure, Harry E. Oppenheimer, Allen D. Jackson, and W. O. Sustins." $15,000 in 1916 is equivilent to $283,000 in 2007 dollars.
The Auto-Kamp trailer featured a tent-style top, two fold-out beds that had sagless spring mattresses, fold-up dinette table, ice-box storage, complete kitchen outfit, and a two-burner gasoline stove. It even featured electric lights, something not commonly seen on camping trailers again until the late 1960's! Originally the trailers were priced from $150 to $200 ($2,400 to $3,200 in 2007 dollars). And this included pneumatic tires, a huge plus for the time. The trailer could be purchased for less if you already owned your own camping gear. The weight of the trailer was about 1,100 pounds.
The trailers could hold 4 people comfortably, but two cots could be placed below the beds as the tent canvas overhung the bed sides to nearly touch the ground. I'm sure larger families could figure ways to add even more as needed. Here is an interesting article in Motor West August 15, 1917, Long Trip With a Trailer. This family crossed the continent pulling an Auto-Kamp trailer with a Model T. Such cross-continent trips were quite an accomplishment in those early years.