Welcome to the forum and congrats on your purchase of a Tiffin. Are you purchasing the Tiffin new/used from a dealer, purchasing from a consignment dealer, or purchasing from a private seller? If purchasing from a reputable dealer, they should perform a comprehensive PDI for you to review. If purchasing from a consignment dealer or private seller, I highly recommend hiring a certified RV inspector to inspect the Tiffin and build any problems that are identified into the purchase agreement. The NRVIA website can assist in finding a certified inspector --> https://nrvia.org/
Regardless of the PDI report, I physically test all of the major components before purchase i.e. slides properly move in and out, steps move properly, A/Cs - furnace - hot water heater work properly, all appliances and entertainment systems work properly, generator operates properly, toilets flush properly (especially if macerator type toilets), awnings work properly and of course for a motorhome that it has been taken on a lengthy test drive to assure engine and transmission are functioning properly.
And I assure there are no water leaks. To do all of this testing means the motorhome needs to be connected to shore power and water at the dealership or private seller's location.
Hope this helps!