Sea-tac area is boorrrrring. Start your vacation right and head downtown. Looks like you'll be leaving from Pier 30 which is down by Safeco and Quest fields (Mariners and Seahawks). Mariners play the Yankees Saturday night at Safeco. Seahawks are out of town on Sunday. There's a hotel called Silver Cloud which is the main hotel for both teams and is right near there. Don't know what they charge. It would be the "Stadium Silver Cloud".
Enjoy your trip! Hope we'll have good weather for you!