This is a 247-hour and 50-minute long road trip around the contiguous Schengen Area on the E-Road network. While doubling back is avoided, it is not disallowed. The goal is to get close to the edges of the Schengen area, but excessive doubling back is not necessary. Furthermore, remaining on specific roads is also not necessary, as any part of the E-road network is fair game. Also, a rule exists to avoid the use of ferries.
For more information about the International E-road Network, click here.
Included below are resources to view the trip in Google Maps and Google Earth.
Here are the legs of the trip on Google Maps:
The Google Earth files can be found here: https://drive.google.com/drive/folders/1KmUcAVnZ4WjM6x5nG8V7VwOjkYXtg6xT?usp=drive_link
Special thanks to https://www.gpsvisualizer.com, as their tools are what makes creating the Google Earth files possible.