Hi Vicki! And welcome to the best sharing site of Airstream information -- anywhere!!
Model names tend to change with the times; e.g., "Classic" is a more recent top of the line with nicer windows and home-like interior hardwood cabinetry. Browse the Vintage Airstream Photo Archive
site and you can draw some conclusions -- although it cuts off after 1979. Airstream was owned by Beatrice Foods in the 1980s -- Beatrice was out of their league and infamous problems with frame flex and 'rear end separation' marked longer units of this period. The 1990s fared much better. Just guessing -- but trailers 25' and longer became 8'6" wide in about 1993-1994.
Front kitchen? I'm not the best historian but that may be a stretch. Airstreams have been fairly consistent with either a foldout couch/bed (gaucho) or dinette up against the front windows.
Some of the most experienced folks here have 1990s era Airstreams -- a good compromise on fewer repairs and lower prices. When box trailers get 'tired' they are recycled at the landfill. Any Airstream rewards your labors with long years of usefulness. I hear longer trailers are occasional good finds in Florida and the south as retirees depart to spend their last years closer to home and family. Either way, browse the ASForums classifieds
or at the Vintage Airstream Club
to get an idea of what turns up and how often. Avoid eBay like the refuge of lost causes that it often becomes -- that is only for the very savvy Airstream hunter.
I'm sure you are trying to search on topics of interest -- keep at it for the occasional nugget you'll find. Please feel welcome to ask any and all Airstream questions!