Flights into Sea-Tac Airport are the best route. You may also find flights into Paine Field, a smaller airport north of Seattle.
We recommend renting a car for easiest travel to the venue, and looking for accommodations in Bothell, Woodinville, Lynnwood, or Kirkland instead of in the city of Seattle. You'll be closer to the venue and it'll be less expensive for you.
Travel Note
Woodinville Wine Country
Woodinville is the Seattle-area wine country, with a wide variety of wineries and restaurants. We recommend that you check out Washington State's oldest winery Chateau Ste. Michelle.