Find Your Cruise
The weather will be varied - normally quite cold at this time of year (0-5c), especially as you'll be at sea - take lots of layers.
Princess excursions are quite expensive but normally very good. The advantage of taking Princess excursions over doing it yourself is that if a problem occurred and the excursion didnt get back when the ship was due to depart, they would generally hold the ship or pay for you to get back to it - if you miss it yourself it's your problem! If you feel confident in your abilities to explore on your own, then this can be better, as you then have the freedom to see what you want and take as long as you like in certain places (in tours you dont always get long enough OR you'll be going too slow while less abled passengers are trying to keep-up).