yeah, that would be classified as "fairly minor" for rust in my book.. can easily be cured and coated.. What you would have to watch out for if its seeped up to the floorpan, as that can be trickier to fix. What is that back towards the cat converter on the floor there - that looks like more rust? Do you have photos of that?
The main one is the chasis rails (they are not what you are referring there - those are just the sills..) which are about average for that age, with the usual misplaced jacking and things - they look fairly straight. Not sure whether the rear of the LHS rail (2nd photo) is meant to be like that, looks a bit bent in, although its hard to tell from that shot.
otherwise seems like a good price for those levels of modifications.. if you add the price of a GT2530 turbo kit and a few other things, there is a few $k just there.