2 Remarks on this workout program:
Why is it so hard to find information on this plan? Using a general internet search I finally found this page: http://www.zwift.com/events/series/zwift-fondo-group-workout/ but there’s no link from the Zwift Events page to this page.
The planned workouts are useless for most people in Europe as they are all planned at inconvenient times. Weekdays you want an evening ride and during the weekend you want a morning ride.