We have made this table which will be always up to date for you to be able to join the ride at a time of your choosing:
https://docs.google.com/spreadsheets/d/1T2vrBEoI9IOJ4EFpBQoe7m9qRSvzjQGZtLb6Ogrw8dQ/edit?usp=sharing
From Paris to Sofia the dates are now final.
Later in the journey, these dates may vary by a few days until end of May.
After the departure from Paris (June15th), all dates until Ankara will be final.