Welcome to Airstream Forums from Colorado. It sounds like you are an adventuresome person. Good for you. I admit I'm too cautious.
You can learn all about your new 77
Sovereign 31 here on Air Forums, especially in the Knowledgebase section near the bottom of the Forums page. My friend and I are currently putting his 76
Sovereign back together after some extensive frame repairs and floor rot repairs. It will be a very nice vintage Airstream when we finish it. The links below will direct you to the Knowledge Base and our "project thread" for this
Sovereign where you can learn all about what we are doing.
Last winter I finished my 75 Overlander 27' with essentially the same repairs and refurbishment as this 76 Sovereign. I enjoy working on these old trailers in my retirement. Crazy huh?
Here are the floor plans and specifications for the 77 Sovereign from the Airstream company website, then document archives. It may help you figure out how your trailer was built (e.g. mid bath or more common rear bath) and maybe give you some ideas on what you might like for a floor plan.
https://www.airstream.com/wp-content...rplans-293.pdf
Trigger warning: Starting from a gutted trailer will be costly to get it rebuilt. Doing all the work yourself (except maybe welding) you should budget about $15k in materials and about 1200 hour labor. This is from my experiences. Others have different experiences and are better at it than I am.
Here is a photo of my friends 76 Sovereign, and of my 75 Overlander.
David
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WBCCI #8607 VAC Region 11
KnowledgeBase trailer renovation threads: 69 Globetrotter, 76 Sovereign, 75 Overlander, 66 Trade Wind Such fun !