I live here and I can tell you that Whittier is a waste of time. Don't spend your money on a glacier tour--well unless that's the only one you can do. A better itinerary would be to go to Seward and take the Major Marine tour. They serve a delicous meal and you will tons of wildlife. If you take the 8 hr cruise you will go right up to Aialik Glacier. Spectacular. But you would need to stay overnight in Seward unless you can get there by 10:00am and are prepared to leave around 5:30 and not get to Anchorage until 8 or 9 depending on road delays. To go to Seward and not do a Major Marine tour is a sin. So close to Alaska and never to have truly seen it.
Fairbanks is tough. Nothing there. But the drive up is beautiful. The Westmark, Marriott, Pike Landing, are all very good hotels. The Marriott is the best located right on the river. But nothing there. The UAF museum is a definite must. If you had a car you could drive through Goldstream valley or or Murphy Dome. Alaska is tough to see on just a few days and with no plans to hike the back country you will miss a lot.
Try to swing a flight seeing tour in Anchorage. It's a must do if you really want to see the area. Book early.