Before you sign the papers, ask the dealer to let you live in it one night, that will give you an opportunity to try everything.
Put the jacks down, put the slides out, check all the light bulbs, operate the stove, air conditioners, furnaces, check the fridge and be sure it works on LP as well electric. If it has a washer dryer, run a quick cycle (I'm sure there will be room in the gray tank). Check the entertainment systems to be sure everything works. Look for water stains inside and delamination.
Do a good test drive of about a half hour that way everything will come up to operating temperature. Check all the gauges. Get out and look at step operation, sewer and water hook ups, fresh water pump, exterior lights, slide topper and awning condition. Get up on the roof and check seam sealer all over and condition of appliances up there. Check all of outside for delamination. Look under the slide outs for water damage on the floors.
I am sure I have left things out. Good luck
Bob & Joan Alexander, 2010 Tiffin Phaeton 36 QSH, 2013 Jeep Wrangler (toad)
Lobo & Juniper (woof, woof)