It's very common in amateur events, such as gran fondos, for only a portion of the course to actually be timed, such as the climbs. Aside from the climbs, as long as you finish before the course cut-off time, you're good. Bona fide amateur racers don't take breaks, but those races aren't 100+ miles, but rather either laps around an urban course or something similar.

The only time amateurs regularly do 100 plus miles is when they're taking part in a century and those are generally not timed. People sometimes keep track of both their actual elapsed finishing time and their moving time, which only takes into account the time they were pedaling the 100 miles. But for the most part, there are no prizes or anything like that associated with centuries, just the pride of finishing. People generally set individual goals and what works for one may be different from another.