I run my long distance runs at about an 11:00 minute pace. I can run 1 mile in 11 minutes so the race should take 2 hours and 40 minutes. The discipline is in maintaining the pace. Everyone tends to start the race too fast instead of following a trained-for pace. That can cost you in energy and pace time later in the race.
If I can maintain the 11:00 pace for the first half of the race, then I can kick it up in the second half, but I tend to wait until the last 3 miles or so.
I wear a Garmin Forerunner 205 when I run. I can check my pace and time during the race and then map it after I download it to the laptop at home!
I use Cliff's Shot Blocks for energy during the run. There will be water/gatorade stations every 2 miles.