Looked at an older RV

Looks like a nice rv to me. I agree about checking the frig as they are very expensive to replace. Our slide does settle/pull in at the bottom last so you do need to hold the button down a second or two after you think it's in. I think someone just didn't hold the button long enough. AC units do occasionally have to have the screws finger tightened inside access to keep the seal compressed to avoid leaks - that could be what the water mark is from. I'd go for this , but try to negotiate a little better price.