There's nothing wrong with getting some quotes, I would. But, I also wouldn't be surprised if they're really high. And with that kind of frame damage, I doubt you'd get much more than scrap value for the car unless you part it out.
Looking at that rail just makes me think there's other rust issues with the car you might not be aware of. When I see that rail, the only thing I think is that any "donor" car you'd be getting a clean frame rail from would probably be in better shape than the car you're trying to fix. Which just tells me that you should look for a cleaner car to start with, and maybe use the car you have as the parts car instead of the other way around.
I think its pretty cool that you can still find A-body's in pretty clean, solid shape and not pay a ton of money for them like for E and B body's. But, the downside to that is it doesn't always make a lot of sense to spend a bunch of money trying to fix one that will need a lot of work. You'll quickly end up spending more money fixing the car you have than it will ever be worth, and more than you could just buy a cleaner car for.
