Maybe $2000? Looks good from the pictures provided. Assuming it's a 307 V8? Unless you find one that's below 50,000 miles and garaged, this is what they look like.
Something to keep in mind, the paint on these cars were basically matte from the factory, especially metallics. It doesn't appear "shot" at all. Just aged lacquer. It's nearly 30 years old. Sheesh.
Decent option package, nice color. Maybe they should have offered the "almighty" 442 (same freaking car with bucket seats, decals, and some extra horsepower) in light green metallic.
Delaware isn't really what I would consider "northern", at least in terms of vehicles and rust. Unless the car is parked at the ocean, cars stay very clean here most of the time. There is usually only 2 months out of the year where it's actually cold, and until just recently they didn't use salt on the roads. Cars usually get "Southern rust", ie: rust from moisture/humidity up high if they sit idle outside before they rot underneath (like a PA or NY silty soil/salt monster).
I've seen very few G-bodies with the F41 suspension. Some people don't care or appreciate that, but it's neat in my book. If you want something that handles like a new car...buy a new car.
But, a Monte Carlo SS that's been painted 10x, has a redneck 350, some Pro-Stars, doofball B&M shifter, aftermarket Honda style radio, speakers and steering wheel sure would be a lot kewler and must be worth a lot more than that pile. Where's my black Metallica shirt that's too small for me? I'm hungry for some Slim Jims...