Before taking final delivery, highly recommend checking out more than just the interior. Taking a few minutes to crawl underneath the chassis, and some time to check out the roof, is also important. Issues in these areas have the potential to be much more serious than many interior issues.
A year or so ago I witnessed a guy who was about to take delivery of a new 5th wheel. Fortunately, he took the time to check out the roof area just moments before signing. On the roof were massive rips in the rubber roof just behind the front cap. Someone had apparently driven the rig into some low hanging tree branches. Needless to say he passed on that unit.
Good luck!