Ok I've calculated and in terms of exp efficiency, rafting glitching is still king, unless you can match Act 4 Scene 3 to the timing of how the cycle of rafting glitching is, and that's probably impossible unless you can finish 5 cloakers in 25 seconds.
It goes like this: Rafting glitching > Act 4 Scene 3 > Normal Leveling
The only thing about rafting glitching is that you will definitely be seen, while the other two leveling methods are more discreete.
So say that 320k exp in 20 minutes. 2 hours will be 6x 320 = 1,920,000exp
And Fomor Raid or whatever that Tara castle mission is called, takes 30 minutes for around the same amount of exp. 2 hours will bring 4x320= 1,280,000exp
It takes about 9 million, 15 million and 31 million exp to level 70, 80 and 100 respectively.
<Boring spam method>
Level 70 - 9.5 hours (Average of 1.5 hours a day)
Level 80 - 16 hours (Average of 2.5 hours per day)
Level 100 - 33 hours (Average of 5 hours per day)
<Tara castle leveling method>
Level 70 - 14 hours (Average of 2 hours per day in a week)
Level 80 - 24 hours (Average of 3.5 hours per day in a week)
Level 100 - 49 hours (Average of 7 hours per day in a week)
<Rafting - recalculation>
This is a bit difficult to calculate, so I'm taking a video to guide.
In this video:
http://www.youtube.com/watch?v=obRcbvvsVK4
2 waves/half-cycle per every 10 seconds for a total of 4 waves/1 cycle, and a 12 second buffer time for respawn.
0.16 - 0.43 seconds in the video is one cycle. So 27 seconds for every cycle. We'll take it as 30 seconds in case of server lag or clumsy hands.
Each wave = 4 hobgoblins, 1250-2400 exp each, average about 1825 exp per hobgoblin.
4 waves is about 29,200 exp.
1 minute = 58,400 exp, 2 hours = 7,008,000 exp (This is why I said rafting glitching is broken)