Took our 9th family cruise on Explorer of the Seas (EOS), on a 7-day Alaska itinerary from Seattle - our first visit to Alaska, and only our 2nd non-Caribbean cruise (we did Europe in 2010). Total of 11 family members, from age 4 to age 83. (My wife and I are 49, with daughters age 22 and 19.)
We visited Seattle for 3 days before the cruise, and hit the major sights including the Space Needle (newly renovated and amazing!), Chihuly Gardens, and a day trip to Mount Rainier (via Tours Northwest, also recommended).
Embarkation was friendly, quick, and smooth - what a contrast from Newark (horrible). We arrived at 1pm and checked right into our Junior Suite, which to us is a worthwhile (if expensive) upgrade - the extra floor space, the walk-in closet, and the wider balcony let you "breathe."