Hi,
What city are you looking to buy in?
If you are flying into the USA, then looking to buy a used RV, you can fly to another town, and probably get a better selection or price?
I was looking at the craigslist in Portland OR, and they have several RV's in much better shape, and built in the mid - 90's for around the $10,000 price range. Even a HMC gas model for $11,000 with only about 60,000 miles on it. That one will have a higher resale value, as it was top of the line for a gas model when it was built, with all the options too.
I would say no to all of the above, and keep looking. I was also looking at the pictures of the RV's in the clicky that is quoted above and the low cost Airstream looks like the same picture for several states and areas. This could be a sign that someone took a 'stock' picture, and is trying to sell something they do not own. . . Beware of scams.
If you ask for the VIN number, and run it through the vin decoder, you can at least find out what engine it should have, and perhaps get a 'car fax' on the vehicle, so that you can find out if it was ever part of a major accident, or was a rental van, ect. . .
Also remember that 'asking price' really has nothing to do with what the vehicle is worth, or what the seller will accept in the end. If you think it is worth $5,000 and the owner is asking $10,000, they might accept less once they realize nothing more is being offered for the 'gem' they have such fond memories of traveling all over the country.
Good luck with your selection.
Fred.