More later, but briefly: Very hot, lots of carnage out there, bad calf & quad cramps from 18 on. Held on for a 3:49:32. Not what I was shooting for, but for a first, and given the conditions, I'll take it. I'll post a race report later (including the story of the 'finish line fiasco'). Thanks for all the support!
Oh, and congrats to Adam C. in Florida for guessing the closest finish time. Message me on Facebook with a shipping address and I'll get the movie out to you soon. Thanks!