Our purpose built cat house and runs are in front of our house, so that the cats can see all the comings and goings of our family. There is always something for them to see so they never get bored.
The houses are lined with hygenic wipe down plastic sheeting and the walls are all insulated with roof insulation to provide warmth in the winter. We also have electric power points in all the houses and the cats have heaters or heat pads in the winter or up here in Scotland anytime it feels cold. The whole runs are covered with thick perspex to keep the cats warm and to stop the rain (rain in Scotland never !!!!) getting into the runs.
Outside in the runs the cats have vetbeds on the floor so it`s more homely, climbers and toys.
Our cats are vaccinated against fiv/felv and they do sometimes run around the garden when I am cleaning out there pens. They absolutely love it.