With two cats and a dog, I came up with the idea of a two bedroom apartment for the cats. I used an an old medium sized dog crate that a friend no longer wanted. I replaced one side with an old piece of scrap peg board so I could attach two cat carriers. Now they have their own bedrooms and a lobby with a shared bath. The cats mostly sleep in their respective rooms. Been this way for six years....
Here are two pictures to help my words...
Back of SUV somewhere in route it looks like, can barely make out the grey kitty in the front room.
A better view of apartment after the car is unpacked in MA.