The first time I went there we left at dawn, got there in 1.5 or two hours, shot and came back to the parking lot around 1600 hours or so.
They said it would be hard to find, that some people never find it, but it wasn't all that hard to find, and we didn't have GPS, just that goofy map that you get with the permits. Getting back, however, was a bit dicier, and I swear to you we heard movement that seemed to shadow us in the trees and undergrowth near the last 1/3 of the hike. There are several trail junctures that could easily be confused when the it goes into the creekbeds, and some of it is across very long, flat surfaces of rock where ducks/markers could be missed.
If I'd never been there before, and I were planning a night shoot, I would get a guide, period.