Easy travelling between capital cities

To easily travel between the 4 major cities all you have to do is this:

Horde

you can use the zeppelin system to travel between Orgrimmer and Undercity and you can travel to Silvermoon Citgy by using the Telestone near the entrance to Undercity and at the back of Silvermoon City and to get to Thunderbluff you need to run through the barrens which should be pretty safe.

Alliance

You can take the boats through Darkshore to go to Darnassus and The Exodar and to get to Ironforge you take the boat to the wetlands and run through to DunMorogh and then to Ironforge and then top get to Stormwind you takle the shuttle train.