I'm a fan of putting things on castors. The whole of PD loco is on 4 (reasonably rigid) legs with 75mm castors at the bottom. I put braked ones on the front and ordinary ones at the back - there's a long term plan to move it to a permanent railway room which is not yet built, but I would expect to leave it moveable, if not mobile, even then. I hope to build the other "modules" in a similar way.
It allows the whole layout to be moved out from the wall to address scenic work at the back - and fix problems if there are any.
Not something you'd want to do often, and needs two pairs of hands, but...
atb
Simon