We did a twelve day cruise tour with Princess and couldn't have been happier (2001). We sailed northbound out of Vancouver (book starboard side) and disembarked at Seward. Stayed one night in Anchorage (at the historic Captain Cook hotel) and took the Princess domed railroad car on the Alaskan RR to the Denali Princess lodge. The train trip was narrated and everyone watched closely for wildlife. There were excursion options to review on the train so that once we got to the Denali Princess lodge you knew what you were doing. We chose to go white water rafting on a river created by glacier runoff (33 degrees, but wearing a dry suit). This was lots of fun. We took the Naturalist tour in Denali -- the only day the weather and wildlife didn't cooperate, but it was still great! Continued on to Fairbanks were there were several excursions already part of the package. They were fun. Additionally, we flew north of the Arctic Circle and traveled about 30 miles on the Alaskan highway (unpaved and dominated by semis involved in the oil industry) to the town of Wiseman. A very interesting and awesome experience. We needed a vacation to get over our vacation. That is just the way we are; however, you can do as little or as much as you wish on these cruise tours.
Back to choosing a line for cruise tours..... I would go back with Princess without hesitation. The other reason we keep going with Princess to AK is that we like the cruise itinerary because it visits both Glacier Bay AND College Fjord. After seeing them both, I couldn't bear to revisit AK and only see one of them.