Fleche
That route is for a "fleche" (wikipedia definition
here.) It's a team event, where the 3 to 5 riders on a team can draft each other and help with mechanical breakdowns. They check in at "controls" to show they've ridden the whole distance.
Measuring up
Don't worry about comparing yourself to others. There will always be someone doing a challenge that seems impossible to you!
For instance, the record for mileage in a year was just broken by
Kurt Seavogel, over 75,000 miles. That's an
average of over 205 miles a day, every day for a year.
On the other hand, the casual rider's group at work was amazed by my 50 mile ride (most of my rides are 30-40 miles). They usually do 10-15 mile bike path rides (which is a decent challenge on older hybrid bikes). But even those shorter rides are impressive to non-riders.