If you bought the unit new, I would be informing Forest Rive that I was going to pursue help from wherever I could, including the attorney general's office for the state you live in, and any media personnel that do reports on consumer's issues. If the unit was new, then I would definitely be suspecting some water leak(s) and subsequent damage. Prepare a detailed document every communication and contact with Forest River and the dealership.
Was the smell evident when you first picked up the camper at the dealership? If so, then the dealership should have known there was a problem. If you purchased a used unit, you may be out of luck, but it certainly would reflect a dealership that didn't care what they sell.