Use a plastic tote for a litter box. Gives the cats much more room. Also on this site be sure to read about the near perfect litter; chicken feed layer crumbles as a scoopable clumping litter alternative! It WORKS! litter box -- maybe a lid?
DIY Mess Free Cat Litter Box - Simple (anyone can do it), really cheap, and best of all IT WORKS! get some yourself some pawtastic adorable cat shirts, cat socks, and other cat apparel by tapping the pin!
DIY cat furniture, IKEA hack: TRENDIG 2013 tray table with cushions made from GURLI throw. Huge sisal mouse from Zooplus. Edit: GURLI is not cat-proof so make cushions from stronger material :) by haollila