A few years ago I used to walk 2 - 3 hours a day. Of course, I lived in Chicago, did not have a car and was too cheap to pay for public transportation. BUT I made that choice also. Meaning, when I had to go somewhere within walking distance (grocery store, friend's house, church, work, etc) I made a choice every morning to walk instead of take the bus, get a ride, etc. It was so much easier and exciting than the treadmill.
Once I started walking to my destination the time flew by. AND once I walked there it made no sense to me to NOT walk back. So that meant daily trips to the grocery store, etc. But it seems like so much less of an effort when you are walking to a destination as opposed to using gym equipment. Try it!