As of the First Half of Chapter 6 update, there are 2 and a half in-game weeks of content. Time depends on your reading speed. As far as finishing the game goes... I currently have no plans to "finish" it in a traditional sense. I have four story arcs planned, and we're nearing the end of the first one. I plan to keep updating the game for the next few years so... I suppose it'll be finished when it's finished? Sorry if that doesn't help. I plan for this to be a very long game.