The course is actually an out-and-back, but for simplicity we'll call it a loop. You will run 3.75 mile loops, hitting the turnaround in 2.1 miles, then you'll run then route in reverse. One section is bypassed on your return trip, and you'll hit the start/finish after 3.75 miles. Then you do it all again. How many laps can you run in three or six hours? It's up to you.