A movable storage assembly has first and second mobile storage units that are selectively movable towards and away from one another and are equipped with a deployable and retractable (or installable and removable) platform to facilitate access to upper regions of the storage units. The platform is movably coupled to one of the mobile storage units and can be repositioned between a deployed or installed position in which the platform interlocks the first storage unit to the second storage forming an elevated walking or standing surface therebetween, and a retracted or removed position in which the platform is partially disconnected to allow the first mobile storage unit to move independently and into close proximity with the second mobile storage unit.