In Alaska the fireroad, single track, power line hills, survey cuts, equaled to 103 miles with barely enuf gas to make it. That was about 8-10 hours of riding without seeing another soul.
It was odd to start your ride at 6pm and ride through the night (sun not going down) and stop at 4am. You just don't get tired.
They have a mother's day enduro, that is 30 miles of tuff trails and half of the field drops out at 15 miles. It can take the fast guys 5 hours and the slow guys past 8. Just think about the guy who has to account for everyone after the race.
That race was the best one I have ever done, a great initiation to riding and some things I have never done since, even 5 years later.
Oh by the way, the winner was riding an XR 200. Low seat height and light did not exhaust his energy. Isn't that a girls bike (ref. other forum)