I am so happy you found the issues and ran away from that RV!!!!
RV dealers are crooks... I will never trust them! Your salesman was hoping you wouldn't notice the issues and stick you with a pig! There is no way he could not have seen issues that severe!
I encourage you to look at private party sales. You get more RV for your money! When I was looking dealers wanted 50% to 100% more money than identical private party RVs. If you go with a private party RV run away if you don't get a good feeling from the seller. Even before checking the RV out. If you don't trust the seller listen to you gut and don't buy from them. You might or might not find a crook when buying from a private party. You will definitely be dealing with a crook if you buy from a dealer.
Search craigslist frequently. If an RV has been up there forever there is probably a reason it has been. Look for new listings and put a priority on checking those out.