Congratulations on the new RV!
I suppose the key is to make sure that:
EVERY system is fully explained to you, and determined to be workjing properly.
Water (hot & cold)
electric (AC & DC)
heating and cooling
windows and blinds
roof vents and fans
Then you have to look for potential leaks... If you see gaps: let them know. If you see spots where something has been rubbing: let them know.
Are all outside storage bays nice and dry?
Look under the rig. Is anything hanging low or loose? Is there rust all over?
You get the picture: good luck!