Agree with gbopp. I think most members of the forum would avoid a rig with obvious water damage. There is likely hidden rot. However, only you know what you can afford, how handy you are, what kind of time you have to work on the unit, and other things. Keep in mind for RVs, most often age of tires is much more important than mileage. You noted that the tires are four years old. Most RV tires should be replaced at 5 or 6 years, no matter the miles on them. I think you might be looking at a pretty extensive repair/replace budget. Good Luck.