The trail is likely to be muddy with over 4" of rain in the preceding week and the forecast is calling for rain throughout the weekend too. Looks like a good race to try out some new treads.
Having ridden Maxxis Crossmarks in minorly muddy conditions last year at the Tall Oak 6hr race, I don't think it'll be the ideal tread for the trail. The Crossmark is a great all-round tread and I have ridden it in wet conditions (Syllamo, Ouachita & Tall Oak), but it can get packed up with mud and traction suffers. For the mud this weekend, I am going to try either the Monorail or the Medusa.
The Medusa is a specialty mud tire, but is not UST. The tread on the Medusa is pretty serious, and probably doesn't roll too fast.
I don't know if conditions will warrant a full-on mud setup, or I should compromise and run the Monorail in the rear. The Monorail has widely spaced knobs and aggressive shoulder knobs; Maxxis says it clears mud well and gets good traction.