TV/Fifth Wheel combo provide an acceptable ride?

Not a 5er person , but two ideas immediately come to mind,
1. With the rig loaded as you stated above drive a stretch of highway and pay close attention to the ride, then move 300 to 500 lbs from the forward basement area and bedroom back to behind the axles, and ride that same stretch to see if its a balance or pin weight issue.
2. tow the 5er with another truck and see if the problem persist, btw the same could be said with towing another similar sized 5er with your truck.