So it still looks like tomorrow's race may be a wet one. I got a chance to go pre-ride the course just after the duathlon and there is still a good deal of standing water. In fact, I counted no less than six water crossings on the course (most 4" to 6" in depth). However, the rest of the trails have seemed to hold up just fine. Some mud but 90% of it is just really nice, moist dirt.
I've tried to mock up the race course over at Wayfaring.com, but I am not sure if I have done justice to the course (the PDF maps they provide just plain suck). Anyhoo, here it is. The course is mostly singletrack through wood section, with a small amount of climbing, some technical short descents and a little bit of sand sections (especially around Beek's Blight on the PDF map). You should be fine with a hardtail on this course, but make sure and bring some semi-aggressive tires; You'll need some grip on the singletrack and some float through the sand.
I am unsure how the course will hold up over night. It's about 5 PM and it just started raining. You might want to check the regional radar maps and forecast to see what it will be like at race time tomorrow morning. Currently, they are calling for a high of 57F and overcast.