Long wheelbase contributes to the smoother ride. Although a bit trickier to park and manuever in tight spots, my crew cab with 8' bed rides smoothly even when not towing. I have ridden in F-150s that aren't as smooth as my 1 tonner.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.