I did a trip to ANC last year that was only a few days long.
First day I went to Whittier and did a glacier cruise from there. Second day I drove down to Seward and went glacier hiking around there. Third day I went hiking around Anchorage. There's a van that goes up to a mountain east of ANC and there are some very nice views from there. There's also a trail that starts in downtown Anchorage and goes to the airport and further south. It's also bikeable.

I would love to go back and spend a week or two up there some day soon

Also, remember that at night the sun doesn't go down completely, so there's enough light to do things. While human (and to some extent animal) life shuts down, you can still explore nature. Use that to your advantage.