I am doing it right now. My party was around level 9 when I fired the useless monk and started a rogue. It doesnt take long, just protect the character. Missile weapons only, maybe pick up a fighter level on the way up. A little tender lovin care

and they will be in the thick of it soon enough. My partys around 12 with the rogue quickly catching up at around level Rogue5/Fighter2 and doing well.