I need to learn how to build a cage/playhouse for our indoor only dwarf bunny. He needs playspace for when we aren't home during the day, but i don't wanna leave him loose. Please tell me what materials and how much of the materials i would need to build a 37"wide by 24" deep by 54" tall rabbit cage with two landings and ladders to go up to the upper levels. I would like it to be out of wood. Which would be cheaper wood or metal for this size cage?