But then you have to do Shivering Isles. I guess maybe if you're crazy good and you wasted no time wondering what you're supposed to do next you could approach it. I still don't think it's possible though.
My save says "Play Time: 46:04:57", so unless Im reading it wrong its 46 hours. I did Knights of the Nine aswell just for fun and Shivering Isles only took 6 hours.