Partner Thrifty has more options, including the perennially popular Seattle to San Diego. Cars are also apparently needed in Las Vegas, Phoenix, and Denver.
Remember, one-way specials are almost always between corporate stores. Their purpose is usually to prepare for an upcoming big demand season when the rates are expected to dramatically increase, and the company wants to prevent a sold-out situation to preserve some inventory for truly needy takers.
While Thrifty started out as a franchise support business, their SEA and PDX stores are corporate, whereas Dollar in those places is not. (Those locations are owned by the same franchise, with one-ways allowed in-network.)
This brings up again the interesting question about whether or not CA emissions laws are unfriendly to incoming out of state rental cars, and if so, whether or not Dollar/Thrifty chooses to follow it. Some said Dollar has a separate fleet for LAS to LAX one-ways, with CA plates only, from the one-ways out of CA. Some might wonder how many non-CA cars SEA and PDX will give out to go to CA in this case.