How early do we need to disembark in Stockholm for 11:30 am flight?

[puppymama1]

We are booked on the Royal Caribbean Serenade of the Seas 10 day Baltic cruise next June. The ship docks in Stockholm for 24 hours on the last day of the cruise. I am researching flights to Copenhagen and home from Stockholm, which is turning into a full time job! I have learned that it is cheaper to fly out of Boston than Atlanta, so we will most likely use miles to get to/from Boston. The return flight I am looking at leaves Stockholm at 11:30 am, so how early do we need to get off the ship to make that flight? I assume we would have to take our own taxi since RC shuttle service probably doesn't leave early enough? How difficult will that be to arrange? I also realize we will have to handle our own luggage, which is not a problem. Since the ship will be docked in Stockholm, I don't think it should be a problem for us to leave the ship early, or will it? I looked at booking the flights on RC's website, but they are more expensive and the earliest flight they have doesn't leave Stockholm until 12:40 pm, has a 3 hour layover in Paris and doesn't arrive back to Boston until 8:15 pm.. instead of the 4:45 arrival I am looking at. so I don't want to make an already long trip even longer.... But I don't want to miss our flight either... Any suggestions from more experienced cruisers would be greatly appreciated! Thanks!