It would all come down to who the court believes acted in good faith, and in my opinion you would lose if they decided to take this all the way.
This I'm guessing is from the OP's leagal counsel.
I think it could have gone either way - but if the OP had prevailed, he would most likely be out the same amount if not more paying for leagal counsel. It seems that he knew there was a mistake by the dealer and came here to see if anyone would back up his poor judgement.
Too bad you didn't have the foresight to try to have them redo the financing because of the mistake - the 9K would not have made a huge difference in payment and their mistake would have been a bargining chip for you - bad on them if they said no. Moot point because you should have alerted them in the first palce, and maybe gotten some kind of perk for alerting them. You must have liked it since you bought it so no one wins here. Your cheap RV rental comment doesn't score any points either. Hope your happy - good luck.. :o