Poll for the tribe. The plastic in the back has only lasted 47 years...come on Cessna!

So time to replace those back panels. I know about Selkirk but sadly they don't have molds for 1977 Q models yet.

Does anyone know of any other products I should research, or maybe a good brand of duct tape?

Check this stuff out it's really tough
https://wingsandwheels.com/cloth-gap-tape.html

Knots2U has most interior parts available.