Yup, civ pop is spread out across vast distances, and while the Americans aren't wildly popular, it's probably fair to say that for the average Greenlander, life wouldn't change much to go from self-determination under Danish sovereignty, to self-determination under US sovereignty.
Moreover, on a purely practical track, there are barely no Danish forces in Greenland, and little way of getting them there in the face of US opposition/interference, and already US bases in situ.
Logistically, 24 hours from brakes off on a US runway to it all being over?
The planning will already exist - NATO and US doctrine from about 1950 onwards called for rapid US and Canadian reinforcement of Greenland to keep the Sovs away from the radars, the runways, and the SOSUS network.
Genuinely, they could do this on the second day of the Trump presidency without breaking a sweat.