I have a 1961--pretty close in period with your 1963
. I posted a photo of how our trailer looked before we gutted it in 2005, with the curtains in it. I think as far as fabric is concerned, what you decide to get is largely a point of personal taste. However, there are a couple of things I learned in making my drapes.
First of all, traditionally, Airstreams of this period had single pleated curtains (something I didn't realize until after I'd made triple pleated curtains). So figure every four inches or so, there's a single inch-long pleat of material that sticks out. The pleats stay firm and in place by an approximately 4" wide header of interfacing (available in stores that sell home dec. fabric) that sits inside the top edge between the fashion fabric and the lining.
Second, it is really
worth while getting blackout lining material. Yes, it is more expensive, but it makes the curtains last so much longer. I made these curtains in 2005 and only took them down recently when cleaning up the trailer to take it to Frank's Trailer Works a few months ago. There are no signs of UV damage and the curtains are as good as new. So--long term, well worth the bother and effort. By contrast, a friend who made curtains for her canned ham with fabric lining has had to replace them twice since (even though I used more delicate fashion cotton and she used sturdier barkcloth).
I blogged about these discoveries afterwards (as well as hardware issues I ran into). You can find this here
I hope that helps!