Would do neither prepackaged tour. Have organized multiple tours all are similar except for duration.
Fly to Anchorage. 2 nights. Alaska State Museum and various sights
Drive to Healy. Tour Denali on the way there. Overnight BnB in Healy
Drive to Fairbanks. 2 nights. Lots of attractions. Cleary Summit and Chena Hot Springs get a taste of rural Alaska.
Return to Fairbanks either direct or via North Pole,Glenallen (overnight) to Anchorage.
Return car. Shuttle to Whittier.
I note Seward is a great town with lots to do. We cruise other lines to cruise our of Seward and native full day boat your, Exit Glacier etc. Very pretty. Need 2 nights. Pier 5 minutes from town center.