I see this is still on CL. This is a tough one, I'm not a body guy so the rust issues scare me from it but for a metal worker, this is very saveable and would be a nice car when done. As stated, the interior looks very nice. I think it could get 2K for the right buyer but that's always the key. Every car is only worth the price someone is willing to actually pay regardless of what everyone thinks it should be worth. $3,500 with the amount of body work needed is too high IMO. If someone started popping body panels for C-Bodies, it would be a whole different ball game but that's wishful thinking.
As far as a winter beater, I'd rather see it go for parts then quickly deteriorate as a winter beater. At least in the land of road salt, Pennsylvania, one winter and there wouldn't be much left to salvage even as a parts car. Right now there are still parts to be saved.