how to train for a 24 hr mtb

Ride a bunch. Simple. But seriously, as this will be my first time ever doing an event as a member of a team, there has to be a different strategy. As riders will take just over an hour to do a lap, I have been training 2 to 5 times a day, short and sweet workouts. Most workouts are under 3 hours, with a lot in the 60-90 minutes. Also riding when tired seems to be paying off. Does anyone have an opinion on this one?