Why do you assume you have to go through all the zones?
For one, I imagine that Dornogal will be close to the border between the Isle of Dorn and the Ringing Deeps, so that is one zone you will almost certainly not have to get through.
Then there is the very likely possibility that the Ringing Deeps has passages to both Hallowfall and Azj'Kahet. Probably even fairly high up.
It hardly seems unreasonable to expect players to go through half a zone to get to a different one.