Welcome aboard!
You'll need two checklists
Functionality
Appearance
If each of you concentrates on one of the lists: you stand a much better chance of catching any issues; before they become problems.
Anything not solidly attached, scratched, missing or sloppy is on one list
The other one is for checking out the functioning of ALL of the systems in your rig:
Lighting
outlets
plumbing
Entertainment
Sewer connections
The fresh, gray, and blackwater tanks
generator
awning
levelers (if equipped)
drawers and doors should move easily, and latch securely
refrigeration
I've probably forgot a whole bunch of stuff to check. Other folks can shime in with their list of favorites.
Good luck!