For the 50km and 100km, you will run a small out and back to get the mileage dialed in.
With that, note that the first lap of the 100km is a couple tenths of a mile longer than the 2nd lap. So when you finish your first lap, you only have to cross the timing mat and head back up the straightaway you just came in from. Nothing extra is needed that 2nd lap.
Elevation Profile - 2017 course
Keep in mind, the aid stations for this event are self-supported. This means you put your supplies at the aid stations before the race starts, and pick them up after the race.
We provide a bit of overhead shelter, ice & water. That's all. The rest is up to you!