If anyone else has any suggestions please let me know
Well you could move......and then also......and put that over there..

Looks good. I know its a welded steel frame but you might want to look at the junction between the side walls and the bed, you might get flex there. Also can you add any bracing the ends or will that hinder your access? maybe look at at a removable end braces?

To help with the resonance it might be worth unequally spacing the bed supports or at least move the central leg off centre, if that makes sense? vibrations have harmonics at multiples and divisions of the base frequency so by having equally spaced connections you can unknowingly increase the vibration.

What is the bearing spacing on the y axis?