Just 3.5 hours of easy endurance. Try to keep the cadence above 85 rpm. You could go for a solo ride or a nice group ride. Or even making it an indoor ride. Some short efforts are perfectly fine, as long as you keep it easy for the majority of time.
Explore this cycling workout
Try the JOIN cycling app to export the workout to Zwift, Garmin, TrainingPeaks and Wahoo.