Oh right I did not consider the time before Star Trek was frequently repeated on TV or available on DVD/Streaming Services.
Just for curiosity's sake, which is the one novel you'd like to see adapted and why? Something to do with the First Contact? Or one of the Rhiannsu books?
Although I read and enjoyed many ST novels back in those days, my ONE ST novel is the "The Final Reflection" by John M Ford.
If it were just a random scifi novel, it would still be amazing. But as a ST novel it is superlative.
It extrapolates from the few brief Klingon episodes (up to that point) and fully fleshes out this truly alien race. Language, psychology, society and physiology are all explored and reasons given for Klingon aggression and expantionistic behaviour.
TFR took the Klingons from a 2D "baddie" alien species to a 3D almost sympathetic people.
And it is (imho) a far better and deeper portrayal that the viking-biker, honour obsessed "Warriors" of TNG onward.
All in all it is one amazing book.