And then she jumps into the other ice mover and leaves. What became of her?
We don't know at this point. One one hand we can say her fate is as unknown as what happens to Giles and MacReady after the Carpenter movie. On the other hand its inferred the snow-trucks have the gas to reach a nearby Russian base which she'd probably head for and we'd see the results of that in a sequel if one is to be made.
Traveling 50 miles in that truck, depending on its speed and terrain, probably would have taken a couple of hours and that's assuming she even has a direction to go in. She's probably there by the time the Carpenter movie "starts" and whatever adventure or events happens there would occur during the course of the first movie's time line (spanning several days.) It's possible, that the events could be times to allow also for the survivors of the Carpenter movie to meet up with her and the Russian base.
Your take on the possibilities is a bit more optimistic than mine was. I automatically assumed she was done for (perhaps just viewing the 1982 film the night before had something to do with that, as those characters have no vehicle to escape in). Did they say the Russian base was 50 miles from the Norwegian base? Did they mention how far the spaceship was and where it was in relation to the Russian base? I know they showed at least one map/image but the information did not stick in my brain.
Not mentioning the American base is slightly irritating. I mean it can't be too far. Or maybe it was very far away from the Norwegian base and the guy in the helicopter is just a really, really bad shot. And has a ton of ammo.