Build a cat house in your back yard or cat run. It is a little enclosure that you can put your cat in so that he is safe but still can enjoy the great out doors!
Er, I think it depends on personality and whether they are an indoor cat or outdoor cat. Indoor cats may want to see the outside world and will go farther when they go out then outdoor cats who have explored many places. If one cat is more daring and adventurous than the other that one will want...