I was trying to find closeup pictures of mine, I thought they looked that bad, and they really were no problem. Maybe they weren't as bad as yours? Here is a picture after the seats were out, and then a picture after the rubber was out.
All the rust you see in that second picture came off to bare metal with a wire wheel on my angle grinder up until the wheel well, where I had to cut and patch a little bit. There was no real rust under any of the seat connections.