Recovery is gonna be your biggest issue, If you havnt allready got a pair get some skins compression tights, and get em on as soon as you finnish. All the usual stuff keep well topped up on liquids and fuel. Ride within yourself dont push to hard.
No specific training other than the fitter you are the quicker you ll recover. Give yourself a good 2 weeks easy riding before the event ( Tapering Down ) and take a weeks leave after..youll need it

Best of luck. Are you doing it in a team or as an individual.