Did CX889 - JFK to YVR just last night and I wasn't looking forward to the 45 min drive home, never mind the 3/4 hours to Seattle! If I were you, I'd make a reservation at The Fairmont Airport - probably one of the best airport hotels anywhere - have a good sleep, then a great breakfast in your room, and have the Concierge arrange for the rental car to be brought to the front door of the hotel for your departure! The hotel is attached to the airport and is a pleasant 5 min stroll thru International Departures to check in. Enjoy yourselves!