As I mentioned earlier, you can get a run to a certain place, but if my memory serves me well, then you can't progress further than the Gate of Desolation. Even if someone has a quest active, they won't be able to bring you along.
Anyway, I don't see any sense of speed running if you are planning on abusing the game with using other players, multiple accounts etc. As long as they are game glitches that you can use on your own, it's all right. Otherwise you can get a speed runner that clears the game in about 5 hours for you and done deal!