Airstream Land Yachts of the 1960s through 1970s were typically identified as follows:
of the Road - - 30' or 31' depending upon year
Ambassador - - 28' or 29' depending upon year
Overlander - - 26' or 27' depending upon year
TradeWind - - 24' or 25' depending upon year
Caravanner - - 25'
Safari/Flying Cloud - - 22' or 23' depending upon year
Globetrotter - - 19' or 20' depedning upon year
- - 17' or 18'
Bambi II - - 17'
Bambi - - 16'
During much of the above time, International was a trim level available on virtually every Land Yacht. What was included in the package varied by year, but usually included a water filter, some specific interior trim items and in some cases ventilation fans and/or lighting upgrades.
The URL below will take you to a site with plentiful information about Vintage Airstreams.
Basically, the Ambassador will be a tandem axle trailer with either of two typical configurations. One configuration, called a double, features a center coach bedroom with a fold-out double bed facing a wardrobe closet wall. The second configuration, called a twin, has a center bedroom with a twin bed on either side of the aisle. The coach would have typically had a rear full bath with tub and shower and a wardrobe closet next to a linen closet in the bath area. (It is possible that the coach might have a side bath depending upon its actual placement within the 1970s era. The kitchen will be immediately to the left as you enter the door with the lving room to your right - - actual configurations could include a single front lounge with side chairs, twin lounges (one front and one streetside), and if I am not mistaken, a dintte type arrangment may also have been available.
A late 1970s Ambassador will likely have a dry weight around 5,000 pounds with an actual towing weight of around 6,500 pounds when fully loaded for a vacation.
Good luck with your investigation!