Two things: I'm surprised nobody mentioned this. Buy a recumbent bike and try maxing out on bench press as you ride to work. It's unconventional and difficult, but when properly executed...a thing of beauty. After a month or so of that, a 3 miler won't seem so bad. Another thing you might want to do is see if you can find a route to work that is downhill in both directions. Many will tell you that this is impossible because of physics. I say they're only limited by their drive to find an easier way to do something. Hope this helps.