If you do not know the history of the AS, maintenance records, or where it was stored; I highly recommend inspecting the roof and windows in detail. If its leaking or leaked in past, your liable to find interior damage down the road. My Landyacht lived it first 18 years in a tobacco barn in Durham, NC. No leaks and the seals were still good even after I had the roof re-sealed last year.
One problem area I found after taking it to Florida was with the rain gutters. Because of the excessive condensation from two roof AC's I installed gutter extentions on both rear corners. Within a month I had wet carpet on side of bed. Turned out the gutter extension was leaking down the side of the trim where the end cap was attached and coming in at the floor level above the cargo compartment. Sealed it with clear silicon and fixed the gutters. No leaks since.
By the way.....their was one problem with my AS from the years it was in storage. It has very low mileage and the air filter had never been changed. Its a huge canister type container about size of a pool filter. Once opened, we found a large rat nest in the air filter chamber. Nothing live but it was messy