You will love your Alaska cruise.
For ideas on clothing, check out our trip report and pictures at Alaska Cruiestour – The Cruise
You will see that a variety of clothing and layers are the best idea.
If you can fit all you need in carry-ons, good luck to you!
As far as cash, credit or debit cards are widely accepted everyplace you will be. Your needs for cash will be minimal. On board the ship, everything is charged to your account. Carry a small amount of cash and a lot of plastic, and hit the ATM if you need any more.
Have a GREAT cruise!