Kangerlussuaq is a strange and useful place: a former military airfield at the head of a long fjord, far inland by Greenland standards, with open tundra on one side and the ice sheet reachable by road on the other. Many travellers pass through the airport and leave, which is a mistake if they have a day to spare.
The attraction is not the settlement itself but what sits around it. You can reach the Greenland Ice Sheet, Russell Glacier, and tundra valleys where musk oxen and caribou are possible, sometimes all without the logistics that make other Greenland trips hard.
Kangerlussuaq is also the eastern end of the Arctic Circle Trail, the classic long walk to Sisimiut. Even if you are not hiking for a week, the first stretches give a quick taste of Greenland beyond airports and fjord towns.