In "The Expanse", the NX-01 basically heads to Vulcan to drop off T'Pol first. En route she changes her mind and wants to stay on board. They change course and head for the Delphic Expanse. It then takes 7 weeks at a sustained speed of Warp 5 to reach the cloud barrier, according to Archer's log.
By "Zero Hour", I assume it took shorter to get home because the Xindi-Aquatic ship was vastly more advanced. There's also that race's ability to create a vortex, which got the superweapon to Earth in a matter of what, days?