The toilets get dire especially in a muddy race. Take your own toilet facilities if possible. As TJ says there is no space for fancy setups - it's in the woods near a river, so expect cold and mist, and any other sort of weather.
Try a campout before the 'Puffer because it always seems to be colder when you're on the edge of exhaustion and damp. You'll be better able to work it out once you have done that. A wet race will mean everything gets damp. Allow for this. Try not to sweat
Have nothing marginal on your bike, replace any component that you suspect with new. The 'Puffer is no place to be trying to fix things.
Heating is good, but it's hard to move away from once you stop
If you carry a phone, it will allow your support crew to hang around in the heated marquee until just before you come in- if you get reception
You'll find this little courtesy and your own toilet facilities means you get to do another 'Puffer
Solo or team?