@lastnamearya I don't know about the whole path, I started around 3 months ago (20.09.16) and I'm on Calculus B right now, I do it alongside work and university and everything, I think on average I put 2-3 hours a day on it, sometimes more sometimes less.
what I really like about it is it has become a habit of mine to follow the courses everyday, I estimate I'm going to finish Multivariable Calculus in 2 months with this pace