I'm from Alaska - grew up in Soldotna and went to uni in Fairbanks (though I've been living in Scotland for the past 4 years)!!
What would you like to know?
As far as cruise vs. inland travel, it depends on what you want to see. For pure variety of scenery, fly into Anchorage and travel out from there. You might want to consider renting a car to get from place to place, that way you wouldn't be constrained by the train times and can see more (though I hear it is a lovely ride). Public transport is virtually non-existant. The scenery around Anchorage is lovely, especially the mountains along the coast from Anchorage down past Beluga Point and towards the Kenai Peninsula. I'm quite obviously biased towards the peninsula, but hey, it is amazing. If you go in the summer though, be aware that it will be packed full of tourists. If you go to Soldotna or Kenai, PM me and I can give you some recommendations of what to see and do.
Homer (about a 90 minute drive from Soldotna) is also beautiful, right on the beach, it's worth at least a day trip. From there you can take boat trips out to some of the smaller protected habitat islands (if you're interested in seeing some of the wildlife).
If you head north of Anchorage, the scenery changes dramatically. I would recommend at least getting the train past Denali, and having a look round the park. Then up towards Fairbanks. There's a lot to see in Fairbanks, and no matter when you go, there's lots to do. Again PM me for specifics if you're interested. The arctic circle isn't that far from Fairbanks (we were about 60 miles away when we went to Circle Hot Springs one year for our sorority retreat), always a fun photo if the roads are open.
Were you thinking about going any further north, like Nome?
If you do the cruise, you'll go through a lot of the little islands in the southeast, and probably stop in Juneau, Sitka and Ketchikan. Haines (also in the southeast) is also absolutely gorgeous - I've only been once, but it was amazing.
As far as weather, it'll depend on where you go and when. If you're thinking of mid-summer, it'll probably be 50s-60s F in Southcentral and Southeast Alaska, and 70s-90s F in Fairbanks. The farther north you go in summer, the less night you'll have, so most hotels have blackout curtains to help tourists adjust. It can be a little strange though to come out of a restaurant or cinema at 9 or 10pm and it to still look like it's the afternoon. If you're thinking of going in spring, be warned that it'll be wet from all the break-up of snow and ice; and if you go in the autumn, it may a bit chilly (but to see bright red tundra against orange and yellow leaves in the morning is arguably one of the most beautiful sights I've ever seen). You're brave if you go in winter, as it can range between freezing and -10 F in the south all the way down to -40 or -50 in Fairbanks (or further north).
Again, let me know if you have any more information.
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