A good resource is
Cruise Reviews, Cruise Deals and Cruises - Cruise Critic which gives detailed info on all cruises nationally and internationally, the ships used, who you might meet, tours, etc. we went on the Inside Passage with Princess Coral. This and Island are the same ships that tour the Panama Canal in the winter as they are longer and sleeker than many other lines, can get into those narrow passages. I loved our trip. I lived in Alaska when I was 18 to 21 and wanted to see this area again and take the hubby. This trip was exactly what we wanted. If you're at all able to travel without a tour group, Alaska trips are very easy for that. The ports are right in the towns as they are all fishing towns, tour prices are generally much less than through the ship and very reliable as this is how they make their income. And if you check out Cruise Critic, you can also organize tours on line which is what we did. Other cruises I've done, I'd take ship tours, I'm just saying Alaska is pretty easy to navigate on your own. Enjoy!