Ah, the excitement of new toy shopping.....we are all jealous of your situation. First thing of importance is looking for evidence of ANY water intrusion. A water leak through the roof might cause a separation of the filon from the outside shell. The would be a problem that cannot be fixed through normal channels. Run from this situation if you can see large "bubbles" visible on the outside. Mildew and rusting/rotting interior structure is sure to follow. Once you're convinced there is no obvious water damage then go to the overall condition of the unit. Smokers? Pets? Kids? Grandkids? Harsh wives?
You get my drift? See if everything works, for example the water heater, furnace AC units, fridge, etc. Other members will chime in with a number of things I've missed, but keep us up on your progress. Good luck!