I just wanted to give to those still looking to do AD rep. Stratholme and Scholomance no longer give AD rep. The AD has been replaced by the Argent Crusade. You can still gain scourgestones, but the turn-in NPC is now gone.
If you are still interested in this, you have one option. There is a quest chain that starts up with Fiona at the border of Eastern and Western Plaguelands as follows:
Gidwin Goldbraids
Just Encased
Greasing the Wheel
Tarenar Sunstrike
What I Do Best
A Gift For Fiona
Onward, to Light's Hope Chapel
Traveling Companions
Rough Roads
The Trek Continues
Boys Will Be Boys
A Boyhood Dream
Argent Call: The Trial of the Crypt
Argent Call: The Noxious Glade
Once this is completed, you then unlock two repeatable quests that give 2000 AD rep each, and can be done multiple times per day from Lord Raymond George (ghost behind the chapel).
Aberrations of Bone: Scholomance
Annals of the Silver Hand: Strat (Live)
Aberations of Bone requires you to just kill Rattlegore in Scholo. Annals of the Silver Hand requires that you loot a book on a table next to Instructor Galford in Strat (Live)