Airport
Typically the least expensive airport from most U.S. destinations. You can Drive to Port Townsend or take the ferry. Ferry Take either the Kingston or Bainbridge Island Ferry from Seattle. Schedules and tickets: https://wsdot.com/ferries/schedule/scheduledetailbyroute.aspx?route=sea-bi
Airport
Good airport if you are hoping to also visit the San Juan Islands. Ferry Take the Port Townsend Coupeville (Anacortes Island) ferry. Schedule and tickets: https://wsdot.com/Ferries/Schedule/scheduledetailbyroute.aspx?route=pt-key