Hi Lamnethx!
The fastest way to travel to Zek or EL is indeed to find the harbourmaster in East Freeport (should be near the mariner bell, but I only know exactly where to find him in Qeynos Harbour), you can buy a ticket straight to Nek or TS docks. Just use the appropriate bell afterwards. (there should be three bells, one for outside Freeport, one for inside Freeport and the third one is the one you need after buying the ticket)
Unfortunately, it is 60 silver for each time, no problem for me now but that wasn't all that easy when I was 30 and with the inflated spell prices these days. Still, saves a lot of time.
Druids and I believe wizards can port. One can create a portal to a specific location, another takes his group along with him I believe to a druid ring. (as I've always played warriors, I'm not completely sure about who can port or transport and how exactly it's done)
It is indeed very important to pick the bush in the druid ring in several zones, Commonlands, Antonica, Butcherblock Mountain, Greater Faydark, Lesser Faydark. (not sure if that's all of the zones, could be more) If you are a druid you have to do a quest at each of the druid rings to be able to port to them, a wizard has his portal quest too. But other players can only be transported to a specific druid ring if they have been there before and picked the bush.
Not sure if you have a horse, but otherwise you definitely should find the druid ring in Greater Faydark, a very fast way to get near the CK or Steamfont Mountains or BB. Heck, find all those druid rings, always handy.
A very fast way to travel from Commonlands to Antonica or from TS to Nek and ofcourse vice-versa is to use the spires that lead to the KoS zones. At most it is a five minute wait, you can instantly port back down to either of the zones.
A spîrit steed is wonderful, but very expensive, you are too low in lvl as yet to try the carpet quest. (but as soon as you get around 46, it's doable to finish it with a very good group or help from higher lvls)
Not sure what quest there is specifically for a defiler, but I did a whole lot in Zek first, EL is a bit harder. There are several quest chains in Zek, not sure if it is the same for a Freeport character though.