Hey Wayne,
I would only use swivel casters that can be lifted out of the way after moving the table so that the machine stands on its feet and never on the casters during operation.
Also be aware that because there exist no really flat workshop floor, everytime you move the machine you will have to repeat adjusting coplanarity of the machine (fishing line method). So in my opinion I would avoid moving a CNC machine around at all.
There exist no CNC table affordable to ordinary mortals that is so stiff that you could put a coin under one foot and it would really wobble. The table will always distort and require adjusting coplanarity. Even the cast or welded steel tables like mentioned here will distort. Even such machines have adjustments for coplanarity.
The nice thing on QCW frame is that the Any Surface Leveling System Feet are included now, which makes adjusting coplanarity after moving the table easy.
PS: If you need to have the machine out of the way sometimes, instead of using casters, what do you think of Lee’s @TDE Fold Down Wall Mounted CNC Table or @JimHatch’s modification of the Fisher-style table concept to accomodate the 48″x32″ Journeyman which can be seen under Lessons Learned for Flip/Fold up/down Tabletop, or Joshua’s @RockingMallet flippable table variant for the Elite 48″x32″ Journeyman William’s @WmColl46 flippable table with vertical clamping possibility?