Best place to keep cats?

You said you like to keep your cats out in the open, but do you mean inside your house or outside? I am assuming indoors but not in a cage? I have kept them outside but in a cat castle but in the shade under my covered patio. What do you recommend is the best place?
Thank you,
Jackie

Karen says:
Hi Jackie,
I keep them inside my home if I want to observe them up close. They seem to stay on the milkweed as long as they don't run out of food. They will start to "wander" when it is time to pupate so you can either put them in a cage or keep an eye on them and add sticks or other plants and continue to return them to this area.

The cat castle in the shade is another great place to raise your monarch caterpillars. Enjoy!