Here's one way to do it with AutoLocation:
Have 5 variables, distance traveled, previous lat, previous long, current lat and current long.
Start a one time location monitor to get your starting point and once you get it store it in the "previous" variables. You'll need some way to trigger a task to do this, a profile that watches for when you get the AutoLocation Location with the same name as you gave the monitor and a task to save the location to those two variables, zero out the distance traveled and start a new monitor.
That new monitor with a different name and some interval (faster will be more accurate and battery intensive, slower will be less accurate and battery intensive) will track where you go. Each time you get your location, use the AutoLocation Info action to get the distance between your current location and your previous location and add it to your distance traveled. When you stop the monitor (you'll have to find some way to trigger this), convert the distance traveled to whatever unit you want.