When I started commuting by bike 6 years ago (again, after a long lay off), I spent a weekend riding some promising routes. I live about 2 miles from work, but high traffic on the shortest route forces me to take a more wandering route. I think the weekend recon rides were invaluable to establishing my original "base" route with a few other options. Over the years, I have added other alternate routes. My usual route now is about 7 miles one way.

Good luck.