I find all three of the Phalaropes are usually IDable at a distance during fall migration with only a view of the back. Knowing the coloration along with a few other details can pretty much nail an ID, most of the time.

Here is a Wilson's Phalarope which has a white rump with no central stripe on the upper tail like seen on the other two. It also shows no wing stripe in flight. The back is usually almost all light gray and becomes more so as the season progresses. The bird above shows some mottling where some juvenile plumage is retained. When you are at a distance and can't see the bill a few of these points will lead you in the right direction.