SEA is close to the WN gates, but it is very small. Free drinks and snacks though.
PHX is a little hike, but when I am stuck there for more than an hour I head to the red carpet lounge. Medium size, no free drinks that I could see, and snacks.
LAX is one of the easiest for me to use. It is immediately to your left after security and WN practically owns Terminal 1 so you have to be close to your gate.
SNA is also fairly convenient and located near the WN gates.