It's where I do most of my training. Almost all the hills are gentle, Ranging up to 1/4 or 1/2 mile long and gaining a couple of hundred feet. The surface is quite good, though there might be some muddy patches depending on the weather for the previous 2 weeks.
If it's like last year, the worst part is perhaps confusion. There are multiple distances run at the same time (50K is longest) and the course switches around from one trail to another a few times. Nothing horrible about this, everything should be well marked, but just be careful at junctions. Make sure that not only do you turn, but it is a "50K turn" not just for the 10K people.
Also, in countless places you'll run down a gentle grade into a little side-valley, cross a tiny creek, and head back out on the other side. That means that the bridge over the creek is where you turn hard (from running in to out) and you're going fast. Well, the wood plank bridges can be wet and slick. You find yourself skating sideways as you try to turn. Not awful, but take all of those bridges a little slowly.
Also, they say avoiding mud makes you muddier. Don't make anything but the tiniest effort to go around mud puddles - plow through instead. VERY common to see people trying to tiptoe around everything and fall facefirst into the most bottomless mudhole for miles as a result.
I haven't talked to Wendell and Sarah yet, but since I'm injured and not running right now there's a good chance I'll be at an Aid Station.