Alaska Lounges in SeaTac are a work in progress
Just so everybody knows what to expect with Alaska lounges in Seattle...
Alaska has three lounges: D (near security), C (at far end), and N (accessible by train). Alaska generally keeps their flights in these three terminals, but because of all the construction in N, they are short gates and will sometimes use other gates in B and S (international).
The N lounge is great and is easy to access if you use the train. Trains in SeaTac work really well. It's open late - until 11 or 12 I believe.
Due to a recent change that many people have complained about, the D lounge now closes at 8 pm. This is the most central lounge and a real inconvenience when you are kicked out at 8pm or when your gate is in B. While it is the oldest of the lounges, it is the most central too. When D lounge closes, the C lounge get busy.
And C lounge is really nice but not at N lounge level. It is also the smallest and open late. You have to walk to the end of C to get to the lounge and the train doesn't access C right now because of construction.