Gary,

Your coach has an air bladder similiar to a bicycle inner tube that inflates and deflates around your slide. In both situations, slide in or slide out, the air bladder seals the weather out. Lucky for Prevost installed slides, they tease the computer to run the slideroom in recessed from the outer coach side. Then, they can pop out the inner tube and replace with like.
Other non-Prevost installed slides such as our former 1999 shell XL coach, the slide rooms need to be removed to replace the tube.$$$$$$$
Yes, its best you get it replaced before Sant Fe.