You'll need Google Earth. If you don't already have it, it's a free download.
Download the Walking in L.A. KML file of the day and save it to your hard drive. (If your computer saves the file as [filename].kml.txt, rename it [filename].kml)
Open the downloaded file in Google Earth. In the Places pane, the name of the walk should be highlighted under Temporary Places (click on it if it's not). Click on the Play icon and watch. When it's done, "Route" should be highlighted. Click the Play icon again to fly over the route again, more smoothly and from a higher altitude.
Let me know if it doesn't work.