There were two different times when a boyfriend had to build either a perch or a walkway for my cats. One time I had moved to a converted garage on someone's property. It was a nice conversion, and the house and garage were surrounded by a big fenced yard and garden. But, the people in the main house had a big dog. My cat got to roam free, but I felt she would want to be able to get out of reach of the dog if necessary. So my friend build a perch for the cat to climb up on just outside my back door. It was a ladder leading to a platform, built on the deck outside my kitchen window.
Another time, years later and a different cat and boyfriend, I had moved to the upstairs flat in a house, and the stairway was an indoor stair way. To make it easy for the cat to go in and out, my then boyfriend build a walkway from the upstairs window down to the roof of the carport and then a step ladder down to the lawn, also a fenced yard. Both of these worked quite well for the cats.
That's what this photo reminded me of--adapting your house to suit the cat's needs.