Well, you can do what everyone else does there... go see Olympia. They have a nice little beach area right there in town, they also have a rental car place were you can rent a car and drive along the coast or rent a moped and do the same (I'm not a big fan of renting mopeds though). If you really want to see the countryside, then your winery tour sounds like a good choice too.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013