fornarog, What a great popup! We had a 1979 Starmaster 7 that we purchased in 1989 and kept it for 17 years. It had the same great awning with the screen enclosure. First of all, patching screen is not like patching any other cloth. Screening this age doesn't just tear, it deteriorates to the point that you will have to replace it.
We sold it in 2005 after the daughters moved on and we were looking at retirement. In 2016 my youngest asked me to look around and see if anything was on the market, they were just starting to look for a tent trailer. I found one at a reasonable price and went to take a look and low and behold it was our Starcraft. The canvas was in very good shape but the screens were falling apart. Having a very active grandson, I decided to replace the canvas. Bear Creek Awnings were great to work with. I am sure they will be able to steer you in the right directions. Call them and send them pictures. One of the guys there had a similar Starcraft and was familiar with mine. Another option might be to take it to a place that does boat covers. They have the heavy duty machines to sew on new screens. Good Luck.
2017 Toyota Tundra, Double Cab, 5.7L V8
2006 Airstream 25 FB SE
Equalizer Hitch