I've heard that his workouts were a minimum of 60 rounds of various bag work and sparring. That means on top of that, he was doing his sit ups, running, etc.
I've noticed that the mindset of guys who were the hardest trainers is similar...going to "jail" and locking away in a ridiculously focussed mindset that is borderline insane. I know I don't have the mindset to do the type of intense workouts they did everyday as the fight got closer.