First and foremost----DON'T GIVE THEM ANY MONEY UNTIL YOU ARE SATISFIED!!!!
If they are a selling dealer they must/should have a service dept. that is able to fix/take care of any issues that you find.
Some of the members advocate taking a video camera and taping the whole PDI. I think that is a excellent idea. The older I get the more things are not retained in my head. With the video, if you have question later down the road on something, you will be able to (refresh your memory).
After you are satisfied that everything is there and everything works the way it is suppose to, no busted or missing parts, camp in it over night, either on their lot or in a campground close by. Talk to them about doing that and see how they react to the idea. If you notice or find anything, you will be close by so you can come back and get it taken care of.
Good luck. Let us know how it go's. Did you buy in WI.?