A couple of tips for those who want this fare.
Make sure you have one Sunday in between departure and return.
If you want to upgrade, check upgrade availability with an availbility tool or by using the upgrade with miles booking selection to see what is available.
However, I was not able to actually book the upgrade online. I kept getting an error.
Instead book on NWA.com in B class. Which works fine online. Then call in and use your miles to upgrade over the phone.
Booking in B will net you another 25% bonus of elite qualifing miles.