I really suck at climbing, to the point that it takes a while for to recover from a climb if I let my heart rate get too high. The only reason I'm hesitating is because of the climbing; 15 additional miles of flat riding or near-flat riding wouldn't be too bad for me, but the 15mi course (pdf) has 469ft of gain while the 30mi course (pdf) has 2,428ft of gain.
That being said, I'm leaning towards just going for the 30mi and taking it at pace that keeps my heart rate at a reasonable level.
Chris, hope Ben feels better soon. It sucks to be sick