I'd Priceline it. You're not going to have much time on the ground, and most of it will be in bed. I'd rather be at the airport and be able to sleep a little later. Check betterbidding.com, recent bids are $40-$45 for 3* SEA hotels. I usually get the Doubletree or Hilton, only once did I get the Holiday Inn. Of course there are no promises on what you'll get. It's going to take you longer than 20 minutes to get from the Fairmont downtown to the airport.