Being that Stephen King lived in Boulder, Colorado, there are many books he chose to set in that state, including: The Stand, The Colorado Kid, Doctor Sleep, The Shining, Misery ... to name a few.
I totally agree. Some other possible answers from Monk, the TV show: Monk: Okay, what's back there? Let me guess. Fields of reefer. You know what I mean: Ditchweed. Boo. The old Ali Baba. Magic Dragon. Bambalachi. Yellow Submarine. Black Bart. Doctor Giggles. Kentucky Blue. You know what I'm talking about. I'm talking about Railroad Weed! That's right. The Devil's Parsley. Skunk, Splim, Splam, Mooster. Side Salad.
I fell in love with Colorado at a young age when we would take my grandmother to visit her brother there each summer, and we'd explore all around the state until she was ready to go home. Such an awesome place.
I confused myself on the "highest mountain" question by trying to put in "Elbrus", then thinking "no, Elbrus isn't in Colorado, it's in Georgia... wait..."
I'm not sure but I don't think that Colorado is named after the river - it's more likely that the river is named after the state, in fact, it was called the Grand River until an official name change. Everything I have read or heard, Colorado refers to the red sandstone.
Portions of the book are set in Colorado, but I think "primarily" is a stretch; many important scenes take place in other parts of the USA. That said, I also tried it before guessing one of the accepted answers.
There's absolutely nothing wrong with the question, but I'd like to note for the record that "Where the Columbines Grow" is also our state song, and is quite good as ballad-style state anthems go