If you don’t mind a redeye this one is a heck of a deal. You are talking 24hr of just about non stop flying but all domestic with decent shots at upgrades and 757 service on the long legs. It does work both ways and a bit HT to reader Wayne who tipped me off on this one.
For the best and lowest CPM you will not find this until January 2016 but my guess is you may need some MQMs then too. You can find the same price on many weekends, including in 2015, but via other airports that have a much higher CPM. So, in ITA Matrix be sure to use the switch “DL+ X:SEA” both ways for the best price.
Here is what I found from MCO:
7,206 MQMs at 4.2CPM
Bookable on Delta.com
Lastly, do always consider the fact that, with the current Delta AMEX Platinum card offer for both the personal and business cards, 10,000MQMs for the card fee is sub 2CPM and after $100 statement credit sub 1CPM mileage run from home! 😉