If you can book it at ITA or Orbitz for the price you find, then you are in big, big, unheretofore experienced luck. But chances are that the NWA.com fare is the only thing that is really available, and you can keep getting kicked over screen after screen on Orbitz while they tell you that the fare is "no longer available" until they match exactly what is available at NWA.com.
If you want to screw around with bogus listings at Orbitz, et. al., it is very tempting, but if you genuinely want to fly NW and want to see what is ACTUALLY bookable, you may as well just go to NWA.com and see what you will get if you keep getting cycled through the Orbitz "no longer available" screens.
