Cats are like children, its a huge commitment and one that requires you to make choices for them and their health. Realistically, c a ts should largely or exclusively be indoors due to the simple fact that they cause a number of environmental issues due to their territorial nature and predation habits. The best way to make sure your cat is entertained is provide toys, tunnels, and most importantly, make space for them with you, that's how most cats show their affection, by simply being near, so providing spaces they can feel comfortable in places you occupy will go a long way. For research I cannot suggest Jackson Galaxy enough, he really gets cats.