Just a suggestion, but when you are heading up the very long scree and talus field to get to the notch between the Keyboard and Pagoda, stick to the left about half way up. There are a series of solid ledges running up the granite that make for some fun and relatively easy climbing (easier than messing with the scree!)
This route doesn't seem to include the NW face? It seems a little misleading to me, as I kept rereading it to try and find a NW face description that I could use from Chiefs Head. Correct me if I'm wrong please.
It's a typo. It should be northeast. From Chiefs Head, the easiest way to reach Pagoda should be via the southwest face, which Gillett rates at anywhere between 5.2 and 5.6.
Thanks for the correction and sorry for the confusion. I edited the page.
I guess the only way to find out if there is a Class 4 route is to go up there with a rope and do some scouting.