When I went through the ministry Zandalor did the main floor portals right after the two upstairs. I had the other 3 sub-quests done, though, so I guess one or more of them is a prerequisite.
In Keara's fortress opponents will spawn each time you try the door to the inner section of the headquarters without getting the correct name for each of the statues. A couple of people have used this place to get up to level 40.
