check out the american cruise companies... the more popular ones include
Royal Caribbean and
Celebrity Cruises who both travel to Alaska.. Their itineraries on the website are usually quite detailed.. I haven't been to Alaska, but I've been on Royal Caribbean to the Caribbean.. the travel style is OTOT... unless u are willing to pay extra for land tours each time the ship docks (This may be different in Alaska, do read up on the websites). Try to find itineraries with more time on land.. some don't spend much time at the docks, which leave you with no time to move around and travel. (Alaska is so big, it'll be a pity if u can only explore the coast) Other than that, there's also the ship size, facilities, age, and programs available.. choose one that interests you, or u'll have a boring time on the ship...
Do your research. There are 2 ways to book, through agents in singapore, or by urself, booking a flight, hotel and the cruise separately. you need a hotel to stay before/after the cruise, unless your flight times are going to coincide very nicely... overall cost when i last looked at the natas fair, it was about 3k+ per pax..
In terms of camera safety.. not much.. just beware of the sea breeze.. it's salty so do wipe down ur camera occasionally.. and the wind can be pretty strong.. so always have the camera attached to your body unless u want to feed the fish..
here's some other popular travel sites to help you out...
http://www.travelocity.com/
http://www.orbitz.com/