#1 on the barn door. Smallest wheels possible. A drapped fabric of some sort would be a hassel.
I would suggest going to Jo-ann fabrics where they sell a foam backed BLACK matte fabric and glue it to the sliding doors.(spray glue) The matte black is extremely helpful for creating the depth of image. Don't use anything bright or visually stimulating.No art work, no design. You want to see into the darkness as the musical characters will appear. NOTHING does a better job creating this illusion that the matte black. This will be a huge upgrade to your enjoyment of stereo. Dim the lights and be blown away!