Dan at Archaeopop has just put up a great post on a new map website Omnes Viae which allows one to plot routes along the old Roman roads. You can read Dan’s review – http://archaeopop.blogspot.com/2012/03/more-ancient-map-madness-omnes-viae.html
You can see the actual website here- http://omnesviae.org/
It is pretty amazing! The website even has 2000 Geo-located Roman towns that you can plan your trip to.