As you said, it'll be different for each person. Like you I whizzed through the stage 1. I'm on stage 2 now but haven't really looked at it properly. You could technically say I have been at it two weeks but I've only watched 1 video! I have done a bit of music theory before so I should hopefully also go through it relatively quick when I do focus on it. I've also been mucking about on Rocksmith and they have a guitarcade game with scales so I've got some knowledge of those as well.
I think for me a couple of months might be a good answer, after I've consolidated everything and am happy to move on. I'm personally rather conflicted about what I should move onto next. My favourite genre is rock, but I really like country and I fancy trying out the blues! Might have to pick one out of a hat.