Rozen Maiden box?

Now, I have a good idea. I'll be cosplaying as the Hina Ichigo (My brother's idea because of the 'cute-adorable-and-tiny-and-always-throwing-tantrums' part. Thanks Ash.) Anyway, my idea was to make a rozen maiden box to take with me. I want something very light I can fold away, so I thought cardboard? But what carboard box will do? I can paint it all easily, and decorate it, but Idk DX Something like a 'wardrobe box'? I can find cardboard boxes easily and for free from stores, maybe I can mod it so I plaster up the sides and make an opening on the side so I can get in and snuggle down, so if someone opens it they'll see me just laying there? XD Any suggestions would help a lot. Thanks!

P.S If I put this into the wrong category, please tell me. Aishteru ><