I am a level 12 worgen hunter. I have only one quest available in Gilneas City (The Hunt for Sylvanas). It tells me to follow Tobias Mistmantle, but I cannot find him on the map anywhere. I don't have any other quests to do, and I cannot find a flight master to go somewhere else.
Go to where you picked to quest, restart the quest and when you take the quest, walk out of the back door and follow the canal to the left. Tobias will appear there. And he doesn't wait you must stay close to him for completing the quest.
For seeing and not missing him make sure you open your nameplates from UI settings