I haven't seen this run posted yet, but after stumbling upon it while questing I figured I'd put it out there. Basically it is just a repetitive run of the Stranger in Need event in the Halls of Agony level 2 exit.
Start in Act 1, Imprisoned Angel : The Cursed Hold. Take your waypoint to the Halls of Agony Level 2 waypoint, and proceed to the exit for Highlands Passage. I believe it is usually on the east side of the map. Down in the pit, right by the exit is where the event will spawn. It seems to be right around 50% spawn rate in my experience so far. Once you exit to the Highlands Passage you will get a checkpoint. Portal back to town, leave the game, then resume. Your portal will take you back the Highlands Passage where you can immediately go back to the Halls of Agony Level 2. You'll know immediately when you enter the halls if the event spawned by the little yellow dot on the map that will show when available. If you don't get the event spawn, portal to town, quit, and resume. Don't need to reset a quest or anything, and the event chance seems pretty high.
The event itself is easy. There are no elite packs that you need to worry about, and the boss that spawns for the event is easily kitable. On my decently geared wizard I can run it on Torment 6 no problem. There are some white mobs as well for extra experience. The event itself on torment 6 gives 9,537,000 exp and 80580 gold. I timed myself for 15 minutes and without trying all THAT hard to run it as efficiently and quickly as possible, I managed about 190 million exp. Also you get drops from killing the boss, I got 2 legs in my 15 minute run.
So yeah, give it a try if you want. Maybe it'll be a feasible alternative for some people. Maybe I'm an idiot and there are better options, that's likely as well. Regardless, happy hunting!