I heard my name…
Axlerod has it right, it get’s expensive REALLY quick. I have an estimated 150 hours into fixing the rust spots on my car, likely more but I just have no way of counting. Doing the math on that at $60/hr you are looking at 9 grand. For your two grand, that is about 33 hours of fixing, barely anything when you look at it. The good news is they are pretty straight forward to fix, remove all parts that look rusty, plus 6 inches or so on each side, weld in. It just becomes a bitch to get all the seam sealer out and bare metal to weld to, most of it is out of position too, can be tricky, ie not just welding two clean flat plates together on a bench.
Basically anything can be fixed, if you saw my car before you would have sent it to the wrekers. But at this point it is one of the strongest frames out there.
Key issues:
front frame rails: easiest to fix, when the engine is out, there is 3 hours to get it all out so you can weld properly and do a good job, 5 to put it in
Rear frame rails, right where it bends behind the tire: PITA, take out the whole rear end (not too difficult), about 1-2 hours, gastank too
Trunk, very rear lower corner: takes time, oh behind the bumper too
Rockers: If there is slight rust might be able to patch, if there is a hole you will likely be putting on new rockers to fix it all properly, you have to custom fab the quarter to rocker transition, thats a PITA
Floor: various places, can be hard
Overall I used a FULL 4x8 sheet on my car, fixing more then I feel like typing, but with the above key points there is close to 20 hours to get it READY to fix, let alone fix it. SO, if you plan on doing it yourself, not a problem, all you need is time. If you have to pay someone it becomes exponentially unpractical with small increases in the amount of rust.
If you could find someone to fix it for a decent rate, not a shop rate of 60/hr, then you would be much better off. If you are looking at a car, post pics, I will do my best to look at them, but this info should give most a good idea of the problem. Unless it is kinked in two they can all be fixed. (even kinked I guess, but start measuring)