Welcome and best of luck in your search.
I am not familiar with this model, but these are some of the items I would look into.
- have the roof checked for any holes, bubbles, etc. Water is a major problem with RVs.
- have all the caulk on the roof and around the windows checked for cracks, missing, etc. Again looking for places water can enter.
- look down the length to see if the outside walls are bowing out. Water will likely be the cause.
- Put some fresh water in the fresh water holding tank. I would suggest at lease a third full. Probably more if the dealer will allow it. Once the water is in the tank - turn on the water pump and take a seat and be quiet. I would plan to sit there at least 20 minutes. You are listening to find out if the water pump is going to cycle on and off. If it does, there is a water leak somewhere in the plumbing. Have the leak located. It might be something minor that just started, but it could be a major problem. Once the leak is fixed, test it again. Hopefully, the initial time goes by, and you sit in silence while you are looking at the manuals.
- look at the hours logged on the generator. They need to be run under load to be kept in good shape. I would expect at least a few hundred hours to be logged. My year old generator has about 75 hours on it. Make sure it is working.
- take it out on the highway to see how the engine, transmission, and suspension sound and feel.
- walk or bounce on the interior floor. You are looking for soft spots. If soft spots are found, water is likely the cause.
- open the interior cabinets around the roof line. Any discolor is likely water damage.
- test the appliances. Hopefully all work.
These are a handful of items I would look at off the top of my head. Please feel free to ask any questions. I like that the dealer is already putting on new tires, but please check the DOT code on the tires.
My first RV was a 14 yr old Class C with items needing attention. I bought it knowing I had work to do so I didn't pay too much.
Best of luck,