....first of all, a 25 foot trailer is a Tradewind or a Caravanner. The name tells you the size and vice-versa. An Overlander is a 27 foot trailer.
A good source for this stuff is the vintage airstream photo archives at http://www.vintageairstream.com/archives/index.html
The Tradewinds, I believe, all have the rear baths. The center bed choice is either twins, with a bed on each side of the center aisle, or a "double," which is a fold down couch opposite a dresser slash cabinet thingy.
The front sleeping deal is almost always a fold-down couch. Our dinette is fairly unusual. This picture set shows the dinette in front and the twins in the rear: http://www.vintageairstream.com/arch...Tradewind.html