The green route is the shortest and is also the one recommended by Josh. But last time we were there, we had a CM that was walking us painstakingly slow (and what appeared to be on purpose - for some reason) through the castle, and we got beat by at least 50-75 people coming from Liberty Square. Ended up with about a 10-minute wait. It was frustrating considering we were belly up to the rope well before anyone else evened lined up.