Easy leveling tip
If you are i no rush to get to lvl 40, but still want to get there eventually the daily quest "lots of rouges" is the way to go. You get it in Argos after completing some of the first quests in the region. Just level all your civs to around lvl 20, and then just continue doing the quest each day on each of the civs you want to level. The quest takes around 6 minutes to complete and nets around 50k exp. It can also be completed on heroic for additional exp.
It will take you a month or two to max out all your civs. It can seem like a long time, but you wont be spending more than maybe 25 min each day to lvl all your four civilizations to lvl 40.