After more investigation, it appears that the routing for the 2003 US Open, is, as Ken says, play the first, skip over to #11-18, play the tenth, then the second, and then #'s 3-9.
I drew it out on a map to make sure it makes sense. The tees in each of these routings are close together so there aren't any ridiculously long treks on any of these routings.
Frankly, I think the Sr. Open routing makes more sense to me than this, though.