I would piece curtains that I could tie back when I wanted. Or you could always use the doors and cover them with flannel so that you'd have a design wall. If you choose that, run strips of velcro down each side of your doors, wash and put velcro down each side of your flannel. That way if it should get soiled you can take it off and wash it. If you put the velcro on the back side and wrap the flannel around when you take it off you wouldn't see the velcro strips.