The real killer on those long '70s Airstreams was the rear bath. The mid bath models didn't suffer quite as bad with the saggy backend. When We were Airstream shopping we only saw one mid bath 30' from the '70s, thankfully it was a gut and rebuild so we didn't even give it a second thought.
My last two rebuilds were a 1975 rear bath Sovereign and a 1981 Excella II rear bath. Wish I had kept the 74 Tradewind that I had prior to those two. But someone offered me way more money than I had in it at the time. I won't be rebuilding anymore trailers if I can help it, getting lazy in my old age.
Aaron
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__________________ There is madness to my methods
2015 Coleman CM16FBS(traded) 2016 Concord 300DS
2015 Ford Fusion Hybrid following along
Oh yeah after 18 months the fr frame bent right behind the rear axle so bad that placing a 24 in straight edge across it showed almost 3/8 in of daylight