I can see how this book informed my reading choices as a child. While the adults make much of Nelly's calm, mature behavior, I would add that in addition to her kindness, Nelly was observant, a good problem solver, creative as well as being persistent, and brave. While we see Rob do a bit of maturing over the course of the story, I hadn't remembered him starting out as a demanding, erratic brat! He remains fairly impulsive and self-centered while also being anchored by a fierce love for his family.
I loved the immigrant settlers of their Colorado locale. I also was struck by the strong feminist message which was often expounded by Lucinda.
While the original publication date is listed as 1878, there was a minimum of questionable references which make a modern reader sit up and challenge. That said, the narrarator's voice sometimes seemed a bit cloying to my much older adult self than it did to the child who found this treasure in her grandmother's basement.
This was at least a third read, but I'm guessing the last one was 30 years ago.