I had an idea a while back, centring on the Rope Walk. An idea of posts at either end together with a board setting out the distance travelled:so many laps equals a walk to London, New York, the Moon (and back).
It struck me that it would be more fun to know that every month ones gentle exercise, walking or jogging, added-up to a 'concrete' achievement.
I have had occasion to check walking routes in London on the 'walkit' web site. Here, along with points of interest and almost unnoticeable adverts for shops , bars and restaurants along the way, they too give a break-down of calorie-burn.
http://walkit.com/