This is what I would do personally. I would cover the two foam boards with muslin like fabric with a fabric "hinge" so they can be folded into the 4x8. I would take the flannel and make it like a fitted sheet. (?). I would than just lean it up against a wall, it will be slightly inclined but that should be OK unless your space is really limited. If you want to store it just fold it in half and slide it under a bed.