I can't help you with fishing recommendations, but we did the same trip last August. I hope you get to join the 30% club!
If you are on a land/sea cruise, you won't really have too much time in port to go off on your own. They leave you just enough time to do an excursion on shore and spend a little time walking around town before you need to get back on the ship. The excursions offered by the cruise line gaurantee that you will be onboard before the ship sails, otherwise, you are SOL.
Some of my favorite parts....Bus tour of Denali, lots of wildlife, take the longer bus, it's worth it. Telketna, definitely a place like I have never been before. The train ride from Denali to Whittier, awesome. Bring a deck of cards, it's a long ride. Whale watch in Jenuea, wow! The train ride in Skagway to the gold fields, and then the suspension bridge walk. Of course, the glaciers and views from the ship all along the way. We ended our trip in Vancouver and spend an extra two days there, well worth it, one of the nicest cities I have ever been in.
My next trip to Alaska will be for fishing, no cruise ships. I don't want to spend 4 hours on a boat for 1/2 an hour of fishing, I'd rather be out there all day long. This trip was with my wife and sister and BIL to celebrate 25 years for all of us. Next trip is for me. :-)