Both my cats are indoors only, however I would let them out if we were not near a busy road.
Still though, I feel bad sometimes that they don't go out. One of them REALLY WANTS to go out bad.
This spring or summer we are going to build a combination cat run/enclosed patio- I saw a design for it in Cat Fancy magazine.
It's made of 2x4's(I think?) spaced apart for support, then lattice which you can paint or stain. The entrance will be off our sliding glass door in our kitchen nook, and run down about half of our backside of the house.
It will be pretty large, for BOTH humans and kittys (& dog too).
We plan on putting our BBQ, patio furniture, some plants, windchimes, etc. ............and oh yes, some cat trees & perches too.
I liked this design because it looked pleasant, not like a cage, and we will get some use out of it too.