Well, generally speaking, if there is THAT much mold, you're going to be stripping the home down to the studs and starting over.
In that case, you would rather likely have your inspector look at the root cause of the mold and how to prevent it.
That way, when you go to re-do the home and such, you'll know what went wrong and how to prevent it.
Then, you'll want to closely follow steps to dispose of all the mold material. Also, make sure you duct sanitize, not just duct clean.
All in all, it is pretty common procedure. All homes have mold, but relatively few types are the "bad" mold that you hear so much about.