This isn't a travel site, so not sure we can or should attempt to suggest places to go. Alaska is a big place. Are you on a cruise?
But if you have an iPad, Trey Ratcliff of Stuck in Customs has a free app called Stuck on Earth. This uses crowdsourcing to choose popular locations and photos. Like Google Earth/Maps, you can navigate to Alaska, zoom in on specific areas, and with the app, click on spots and view photos taken there.
Batteries will not last as long if they get cold, so you either need to keep the camera from getting cold, or else charge up your batteries more often (or carry spares).
As for lenses, I would imagine you might be taking a lot of landscape pictures. There are some good questions and answers here on the site about travel and landscape lenses.
If you are on water a polarizing filter will be very useful. It will enhance the skies, water and ice.
And make sure you have enough memory cards so that you don't run out.