According to article 6, of the Washington State Constitution,

"All persons of the age of eighteen years or over who are citizens of the United States and who have lived in the state, county, and precinct thirty days immediately preceding the election at which they offer to vote, except those disqualified by Article VI, section 3 of this Constitution, shall be entitled to vote at all elections. [AMENDMENT 63, 1974 Senate Joint Resolution No. 143, p 807. Approved November 5, 1974.]. That would make the state of Washington impractical because of the long duration of required physical presence."

Unless anyone knows a way around this the state of Washington has to bwe ruled out.