I felt the course was fairly accurate through 10 miles. I thought the 11th mile seemed short. But again, without a watch, I couldn't get a real good gauge on it. I did measure the course in 2 different ways:
1) on this site https://www.gmap-pedometer.com/ and came up with 12.94 miles
2) I drove the course the day before, and my car odometer read just shy of 13 miles
And my friend measured it on his bike gps, and had 12.97 miles. If I wouldn't have locked my key in my van, I would've worn my GPS watch and got a reading. The 10k I ran on 7/4 measured 6.15 on my GPS watch, and I know that course is very accurate.
So my best guess is somewhere between 12.9 and 13 miles. If they'd move the start back 1/8 of a mile, I think they'd be fine. I'm not going to obsess over it, since this wasn't a goal race, but I plan on contacting the race director to let him know that many who have run the race in the past believe the course to be short, and runners would rather have an accurate course than a short (fast) one.