Here is the TVFR for the GPS coordinates provided,
25':
http://www.tvfool.com/?option=com_wr...e1c64c06410f5a
30':
http://www.tvfool.com/?option=com_wr...e1c688a554105d
Given the distance between the north end of Camano Island and the Seattle transmitters as well as the obstructing terrain, I would opt for a full size combination such as an Antennas Direct DB8E + Antennacraft Y10713 + RCA TVPRAMP1R preamplifier. Start with the DB8E facing about 150° and the Y10713 pointed at about 175° per a compass.
The TVPRAMP1R has inputs for both antennas.
Be sure to avoid aiming into nearby trees or structures, including your own.