You probably selected "Argosies only" or maybe "both trailers and motorhomes". The latter choice seems like it would get you the MOST results, but I think it only shows people who ticked the box "Both trailers and motorhomes." Either the database or the query is not structured correctly, and I've pointed this out in the distant past.
At any rate, I see that no one is listed under Argosy in CA, but what you need is a trailer inspection. For all intents and purposes, anyone who knows what to look for in a '70s Airstream can do just as good an inspection on a '70s Argosy. Select "Trailers Only" and you'll get 58 results at the moment. Sort by "last visit" to find the people who are most active with the Forums, then you might look for people who list a vintage trailer since they'll be more likely to know about vintage trailers.
I see there's a long-time member in Carmel with a '78 Ambassador who was on today and has lots of posts... that might be a good place to start. Send him a request for help by PM.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill