You can purchase a reproduction owners manual from Airstream. The wiring diagram is rather hard to read. Basically everything runs through the center of the ceiling nose to tail. Wherever you have an outlet or appliance on the side it is a vertical drop down from the ceiling. If you remove the rivets along the center interior roof section you can access all the main wire runs. I confirms this when I pulled everything apart in our 1970 Overlander.
Craig and Carol
1997 34' Excella 1000
1970 27' Overlander, International
2009 Ford F150 5.4L
ProPride hitch with 1400# bars
Past President Southeastern Camping Unit (12)