Help-Unusual amount of rust on chassis-looking to buy

I've seen a lot of nice coaches with heavy chassis rust because they were driven on salted roads during winter. They leave too late from their summer place and wintering in CA/AZ on the way to/from the west hit those storms with salted roads and it wreaks havoc on the chassis. if not properly rinsed.

I've passed up 2-3 coaches because of this situation. My advice is to pass it up as too many issues can arise, not to mention major depreciation to the coach with all the rust when you try to sell it!