Ask lots of questions. There are no dumb questions. Just questions. Have them show you how to winterize-is there a water heater bypass? Is there a siphon hose that is used to add RV antifreeze to the water lines. Where is/are the water drain valve(s). How does the water heater work for this model? Gas/Electric. Have them turn on the propane, test the stove, the oven, see the refrigerator pilot light kick on, and the water heater (as long as it's full of water.) Test all lights, kick on the A/C and the heater. How do the stabilizers work? Sewer hoses-where's the black water and gray water valves? Does a sewer hose connect to the trailer?
Better now than after you drive off the lot.
Just my two cents worth. Also hook up and test all lights. And test the breakaway brake switch.
2012 FunFinder X 210UDS
4-68 watt flexible panels; 1-215 glass panel/4 Battle Born LiFePO4 Deep Cycle Batteries
2014 Ford F350 6.7 Liter PowerStroke V-8 Diesel longbed, SRW