KML

Export Google Maps Route to KML/GPX
GPS Visualizer: Map a GPS data file with Google Earth (KML) - http://www.gpsvisualizer.com/map_input?form=googleearth
 * "Or provide the URL of data on the Web:" (and hit enter)

GPS Visualizer: Convert GPS files to plain text or GPX - http://www.gpsvisualizer.com/convert?uploaded_file_1=&format=gpx&convert_format=gpx&form=
 * "Or provide the URL of a file on the Web:" (and hit enter)

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GPS Visualizer will take a Google Map route (url) and convert to .gpx


 * "You can ignore most the options, just select Gpx and paste the Google Maps URL into the box labelled “provide the URL of a file on the Web” and then press the Convert button"

http://www.gpsvisualizer.com/convert_input

Guide http://bedsforcyclists.co.uk/articles/2014/04/13/how-to-plan-a-route-in-google-maps-and-export-it-to-gpx-your-phone/