I think calling it a frame may be being a bit generous. At least you can probably remove most of it with a wire brush!
As you've bought the car with your eyes wide open, I believe it has found its true owner.
Remember it's not all about the money you put into it, it's more the pleasure you get out of it and that can be priceless.
You are in the right place for support on your journey. Good luck with your restoration, I suggest you take time to read most of the Forum that's what I did. Don't be afraid to all questions you well get nothing but support from here.