Avoid most of winterspring. There are some nice and quick quests there, but its also a lot of annyoing quests where you are to kill mobs that nearly does not exist.

In silithus you get a few quests at 55, but most you get at 58. Skip the field duty quests, it doesnt give any xp. However there are other good xp-inbringing quests there.

You should also probably sweep through BRD, lots of quests there that gives good xp.