That rider took 77 days. Each year there is a race along basically the same route, Canadian border to Mexico border. The current race record is around 13 days.
Then at the other end of the spectrum there are lots of people who go quite slow, but for months. I'm not sure which is more impressive; both show tremendous grit but in different ways.
The only thing that truly sucks is when you can't continue. Like getting two irreparable flats 20 miles away from town in rural New Mexico, or getting an injury that ends your journey.
Hard to explain to people that don't experience it like that, but even if it doesn't feel good all the time, it's basically always still somehow fun.