Too late for your trip this weekend, but here's my $.02...
I was up there back in August and went up from Lower Relief Valley. This was based on the theory that it was more direct as I started from across the valley at the end of a FS road (Silver Creek Mine?). I don't much like the climb from Kennedy Meadows.
I went up the Ridge Lk outlet creek. There's a bit of a use trail on the left side of this creek, heading uphill. Best is to stay on that side of the creek all the way up, I think. Required a modest amount of route finding in a couple of spots.
Schiffrin shows the route further east, below Iceland Lk. But that looked harder to me.
There was a good write up on routes to all the lakes up there on High Sierra Topix site.