We just use furniture that goes up different levels. For instance, an upright piano has the keyboard cover, the top cover and the bench for the player and braces from the legs to the piano body proper, then there is the floor, underneath those things. There are bay windows, TV on on a table (both to walk on). We also put boxes around for them to either sleep in or play in. They also go on, around and under the couch and end tables. Thunder paws are a regular occurrence here.