From Int'l District tram to Seattle airport, fly to St. Louis airport, then train to St. Louis. 7hrs 12min $214. From Seattle, WA train to Chicago, IL then train to St. Louis, MO. 2days 02hrs $415. From Seattle, WA bus to Missoula, bus to Billings, bus to Denver, CO, then bus to St Louis, MO. 2days 00hrs $420.