Congrat on your new RV, use it as much as possable.
Look and listen underneath in the basement while your wife is on top trying to make it squeek, maybe one of the screws came loose , or take one out for a size measurement, buy some more, and install them underneeth like the others that should stop the squeek, Oh if you could use some of that cauking they use when a sub floor is installed between the joist and decking material that will also stop squeeks. good luck.
Pulling a 2004, 2980 RL an oldie but goodie.
Tow vehicle is a 2009 RED RAM 3500 DRW.