The weather looks good! I wish you well. Take it from an old fat guy: go slow.
Using data from last year, and the course profile, I have a new way to feel relaxed with an extremely casual pace, and not get caught up in 'the numbers'. One of my big problems last year was bad math. I've removed the need to do calculations in my head (bad, bad for me after about 10 hours), and hope to just enjoy the day / night / day — as much as that's possible. The cooler temps should really (really!) help.