We took a Gulf of Alaska cruise on Princess this past August/Sept. I found lots of helpful information on cruisemates.com and cruisecritic.com. Both boards have information and forums for HAL which is what DVC offers using points (which I'm sure you already know!). Cruisemates has an Alaska specific forum which is very helpful.
This past July, I sent my parents on a Disney cruise for their 50th wedding anniversary. When they returned, they said that the Disney staff "announced" plans for a third ship. Home port would be in California and cruises to Alaska would be one option.
Thanks for the help. I'll be using those forums a lot in the next few months. This morning I booked our family on the HAL Alaskan cruise through DVC. I was able to upgrade our cabin to a veranda. I've always wanted to go on this type of cruise! Thanks to DVC I'm able to go on another cool vacation destination!!