Well, you've certainly asked a broad question! :-)
Tires, batteries, front hubs (fluid level), generator hours, service records, excessive seepage around the transaxle housing, pull the recall notices from Spartan and all the manufacturers of the coach's appliances by brand and model # - make sure they've been performed if any apply, turn everything else off turn coach water supply pump on, check all faucets for good flow, then close all faucets and listen for the water pump cycling on/off every few minutes or so (hopefully it doesnt or there is leak somewhere). Climb on the roof check the edges and around all the roof mounted items for cracking in the roof materials or signs of water entry. Check inside the coach in all the corner cabinets at the front of the coach for signs of water entry (clearance lights are the most popular place for water to gain entry). Obviously, put all appliances through their paces including HVAC. On your test drive make sure the exhaust brake is working, down/up shifting is smooth and firm -Watch for excessive smoke from the exhaust. While parked idling check engine crankcase blow-by - there should be a small open ended hose that exits out the bottom of the engine area - may be somewhat wet around the mouth of it. After running the coach and it's shut off make sure the air system isn't leaking down anywhere.. older coaches may leak air somewhat but just make sure it's not excessive. Pull up the bed, open the engine hatch and check everything for excessive seepage anywhere - pay particular attention to the cooling fan mounted to the side radiator - it's hydraulically driven and prone to excessive seepage. Run the leveling system and let it auto-level itself. Crawl under and check for any hydraulic leaks from each corner of the jacks. Check the retraction helper springs on each. After retracting, make sure each jack fully returns to it's "up" position (no shiny on the cylinder). Open and close the slides several times, listen for rubbing or scraping - check weatherseals around each when extended. While extended look for worn or shiny spots in the sliding framework or excessive binding. When closed make sure each are evenly flush with the body.
These are some basics and should keep you busy for a day or two :-)
94-Newmar Kountry Star 40-KSDP
Spartan/Cummins 8.3C-300HP/Allison 3060 WTEC-II/25yr RV Tech RVIA Certified/Onan-Cummins Certified