It is possible to view American Line brochures, page by page, online. I found some recently with information and photos of ships of the St. Louis's era. I'm afraid I won't have a chance to go over what I found until next week. In the meantime, however, you can try the same tactics I did. I believe I googled things like "American Line" with "dining saloon", or "American line" with "smoke room", or "American line" with "companionway", etc. You get the idea - google "American line" with any liner-related words and phrases you can think of ("saloon", "steerage", "passenger", "purser", "Southampton"). American Line's penchant for naming their ships after major cities makes researching them on google harder than it is with ships of other lines, but I dug up some great info and photos just a couple of weeks ago, so it's all there waiting for you. Of course, if you had some money to spend, you could probably find old brochures and other ephemera on ebay and the like.
Hope this helps.