Google Maps have one advantage over Google Earth. Google maps can be opened in one's browser rather than Google Earth itself. Also, the Google Maps route-making app has become much better and does permit making and editing bicycle routes. There will always be glitches, but the Google Maps bike app has permitted a credible rendering of the tow path routes paralleling our boats' routes.
The tow-path is scenic and flat and a great foundation for both daily rides and for more demanding rides. Here is the Tow Path route from our start in Castlenaudry to Carcassonne.
View Tow Path Only from CasteN to Carcassonne in a larger map