You can camp up right by the lake. You probably require a backcountry permit. Best to check back with the park.
We hiked out in the pitch black, which I would not recommend doing. Basically it's two, two and a half hours of bear fear and strange sounds to the meadows where you can park on the side of the road. Hope that "helps".
Actually, a bit of both. Stephen Oachs and I were sitting at the Mono Lake overlook and saw some pretty sweet clouds forming over the Sierra at about noon. We gambled a bit - not wanting to shoot the icons of Yosemite - and hit the trail to Cathedral Lakes at about 3'ish. It's a 3-4 hour hike to get to the lake and about 30 or 40 more minutes to get around it and "climb"/scramble up 150ft of granite. It wasn't luck to be there and see it happening but being an alpine environment, it sure was luck to have the clouds sticking around for sunset, if that makes any sense.