What county(s) were you hunting/trapping in?
I mean, I was alive during that time, and spent a lot of time in and around Beaver, muskrat, coon, coyote, fox habitat. So I have a pretty good idea how many animals were available.
I know what it costs to do it, and I know what the rolled up and frozen hides were worth then. To profit $2000.00+ legally in a season (or even 3 seasons) seems impossible.
How the hell do you run a trapline so successfully ? You should write a book.