Just got back from an 8 day cruise from Seward to Vancouver on the Sun Princess. our family including a 16 and 19 year old had a great time. Can't say enough about the ship and crew. The food was fantastic, not a bad meal to be had! Our wait staff was lots of fun and took such good care of all our needs.
We did a helicopter/bobsled excursion in Juneau through Princess with Era helicopters. This was expensive, but indescribably beautiful. well worth it!
Ketchikan was fun watching the salmon swim upstream. We visited the hatchery and enjoyed learning about the salmon and seeing the injured eagles up close.
Just sitting on the deck and watching the scenery was amazing. Don't forget to take a warm hat, gloves and a windbreaker and sweatshirt as it gets chilly on deck.
If you have friends or family and plan to do different things on the ship, you might want to invest in walkie talkies to keep in touch. don't forget the binoculars.
I would definitely do another cruise with Princess, can't say enough about all the amenities.