After seeing the pics of the rear wheel lip area, I would not hesitate a second to pull those 1/4's, tailpanel and outer houses, and put NOS metal on there. Otherwise, you will chasing that rust forever. With NOS metal you never have to worry about the rust coming back. I'd repair the lower sections of the front fenders. Also, check the front leading edge of the hood, Novas are notorious for rusting from the inside out right above the hood lip molding.
I know it has 7k miles, but it's got 35 years of time - that's what's done the damage! Put new metal on that car, a total frame-off resto, and you've got an awesome car when you're done.
Love that color!!