Adam,
On a superficial level, when I got to 18 at PGA West, I immediately thought I'd seen the hole before - bend left, how much to bite off, mounds in the bail out right, open for a run-up shot. However, Ben is certainly correct that the tee shot is easier on the River course because there is a recovery from the junk, but not the water. I didn't think of the double green, because it doesn't really come into play (at Harborside in Chicago the 2 courses share a double green and I hit a terrific shot on the Starboard course 2 feet from the Port course flag; people fell over laughing). There are a few differences, but they seem cut from the same playbook. Mea culpa: I thought this was the original 18th hole (as played in the Women's open), with 18 meadow the original 9th - as I said, the best 18th of the 4 courses.
Jeff Goldman