One thing the girls didn’t do is hit the mapping program.
Even along the rivers you’re generally not more than a farmer’s field from a paved road.
Unless they’d made a hobby out of orienteering or something it’s doubtful that doing that would have entered most girls’ minds, probably going to get flamed but it’s one of those gender differences we’re not supposed to notice. Most guys would probably realize what direction the nearest town was and just go due east (or west or wherever it happened to be in relation) toward it, knowing that they’d encounter a road even in rural Iowa. I’m always amazed at people lost on mountains overnight in populated areas. Just look down, see those lights? That’s where the people are. Go there.