This website, whilst dedicated to pushbike monkeys, has some good routes which (with a bit of imaginative adaption) might well suit bods on motorbikes.
https://www.cyclingeurope.nl/cycling/
https://www.cyclingeurope.nl/routes/rome/
https://www.cyclingeurope.nl/routes/rome/gps.php
https://www.cyclingeurope.nl/cycling/
https://www.cyclingeurope.nl/routes/rome/
https://www.cyclingeurope.nl/routes/rome/gps.php
