Jon,

Everything should be checked for proper operation. This alone can take a long time to perform. If you can get the coach to Prevost, I highly recommend having them inspect the chassis.

You should expect to replace components or even some systems on a 20 year old coach. The biggest challenge will be finding like our similar replacement items. This is generally not that big of a deal. If this coach has an Allen Bradley control system, repairs or replacement can be big deal.

A close inspection of the waste water tank is important. Many of these were made of aluminum and in almost every case will leak. This could result in a need to rebuild the plumbing bay and replace the tank. BTW, many are putting in stainless steel replacement tanks. Personally. I'd install welded plastic tanks that almost everyone else uses.

The suspension components need to be inspected. You will likely have destroyed grease boots. This is common and not something to be alarmed about.

Liberty has never been to generous with sharing electrical diagrams. They are good about answering questions, which is helpful, but sometimes diagrams would be most helpful.

If the generator does not have a start/stop switch on the generator I highly recommend reinstalling the generator self protection system.

Be careful of the information you find. There are some that mislead owners on recommended parts replacement schedules. Of course if money is no object then replacing serviceable parts is okay, but wasteful. Stemco, which bought Goodyear air bags, will tell you air bags don't have a replacement schedule. 10 year old suspension bags are almost always serviceable. Tires are probably the most critical safety item, so I can't fault anyone doing an early replacement of tires. Personally, I would 7 years from my tires. This assumes the tires have always been cared for and inflated properly. House batteries can have a life of 3 years to 10 years based on use and environment. Pole to pole owners that are properly charging AGM batteries should expect 7 years use unless subjected to a high heat environment.

Best of luck on your purchase. When you're ready to upgrade your exterior lighting to LEDs, let me know.