Yeah good point about the age. Rowan's in his early 60s and yet we managed a 500 km weekend last year where we rode a 300 km randonnee on the Friday, spend Saturday supporting other riders on their 300 km randonnee, and then rode a 200 km randonnee on the Sunday.
Plus we've just completed another Century-A-Month challenge ... riding at least one 100 mile ride in each month of the year.
On road bicycles.