Need some advice

Prostate cancer put a kink in our camping plans, but all seems well now, so we are again looking for a good used popup. Our necessary equipment includes an electric lift, a/c, and a u-shaped dinette or kitchen. I found one on Craigslist in Iowa, a 2006 Rockwood with all of our requirements except the popout is a sofa instead of a kitchen/dinette. Price is $6000. Owner sent pics and the only thing he says is wrong is a couple of small rips in the canvas where it attaches to the bottom rails and some staining on the canvas over the Queen side bed. So, we would like, if we buy it, to replace the canvas that's stained. Can anybody tell us what it might cost to do the replacement of only that piece or do we have to replace the whole thing? Also would appreciate opinions on the price. Thanks!