Used this a our descent route from the summit, the slabs were iced and loaded. Follow the bulls eyes painted on the rocks to stay on route, and don't ditch into glacier basin no matter what, 1 1/2 to 2 day hake out to the road.
We camped at the boulderfield below the Keyhole and ascended the next morning. I'd recommend that over starting a hike / climb at 1 am from the parking lot. We were the first to the summit that morning, and had a leisurely walk out. Very nice. You'll need a permit to overnight.