I thought the 14ers.com route description made the crossover point extremely easy to identify. The landmarks were the narrowing of the east gully to that sharp dihedral, and the distinctive red rock sitting right in the gully. When we reached that point, it looked so precisely like photo 11 in the route description that I felt like I'd been there before. If you're not in the habit of studying the large photos on the site, this one is worth taking a good look at, maybe even printing a full-page printout to take with.
We got off-route before reaching the east gully - ascending a different gully which we thought was the "correct" gully but was not. We knew we had gone astray when our gully topped out at a saddle. Nice view of South Colony Lakes, but not the way to the summit.
The move crossing over the east gully was the hardest of the route. I remember it seeming quite a bit harder than Don Holt makes it look in that video.

Once you cross, the short ascending traverse up over the rib, and back down in the west gully, is easy going. As others have noted, a good long look back once you're in the west gully, to identify the return route, pays off on the way down. (But we should all know that by now, shouldn't we?) The photos on this thread really tell that story clearly as well.
A young fellow who climbed the Needle the same day as us told us afterward he missed that return crossover and got into some real steep, loose terrain below that point. But he realized his mistake and climbed back up. (Rule 7 from the Quandary West Ridge Rules: If in doubt, backtrack.)