Hiya
I have a cat run, my partner and I put it together. We built if off the back of our conservatory. The conservatory has double doors, so we can get in the cat run too. There was already a cat flap in the wall when we moved into our house, so thats how my kittys get in and out of the run, they come and go as they please. We have a door into a small holding area and then another door into the garden, so we are able to get into the garden without the kittys escaping. My partner is a plumber and he has put large belfast sink out there where I can wash all their litter trays and they have their covered litter trays in the cat run.

They have beds out there, toys, a log to scratch on and a kitty climbing frame. It's not the gradest thing, and not that pretty to look at, but they seem to enjoy it-and thats the main thing. It's the best thing we ever did building it. In the summer, they spend loads of time out there, day and night and we are able to have the doors open and get some air in without worrying about them escaping.

I will try and get some photos over the weekend and post them for you to have a look at and get some inspiration. Hope that helps.
Nicki