I use a real tree up the middle and then secure some of the fake vines to the screen using coated wire. I took apart the wire used for doorbell wiring and cut it into short lengths. It will go through the screen and will hold up even to my largest male panther.
There are special trays made to go under your washing machine. I think they only go to 30". Check Home Depot or Lowes. They may be able to get larger ones. I thought about using these and may still.