Stormwind Harbor goes to Night Elf island and Borean Tundra (northend) depending on which boat
Night Elf island has a boat to return to SW and a boat to Exodar. Also a FP to Darkshore.
The Wetlands city, Menthil Harbor (spelling) has a boat to Theramore (Duskwood Marsh) and to Howling Fjord (northend) depending on the boat.
Booty Bay (Stranglethorn Vale) has a boat to Rachet (Barrens)
Have I missed any?
Other than that - you could always ask/pay a mage to port you to Darnassus or Exodar or Theramore.