I wonder how long the rough-cut opening of ROTS ran - the version with Shaak Ti’s death scene, the Jedi descending through the liquid fuel tanks, and Anakin leading Palpatine along the upper guiderails of a hangar bay. Must have been waayyyy waaaaayyyyyyy too long.
I remember reading somewhere that the first cut of the film ran well over four hours. So I’d wager it probably takes a full hour to get to Coruscant.
I’d also imagine that the whole thing was nearly unwatchable because about half of it was likely overlong animatics sequences (see blu-ray extras).