if you or someone you are really friendly with are handy with tools and maybe a welder, low-ball the dealer and use the money saved to fix the problems yourself. All the "parts" can be replaced, no problem. the frame could be a major fix, but also fix-able with a grinder, a mess of rust-neutralizer and maybe some welding. Then just keep an eye on things underneath and enjoy the heck out of your RV.
If the dealer initially says no to your offer, walk away, but leave your phone #. I'll bet he calls with a counter-offer.
