That book is so flawed it's not funny, I seriously question if he ever went to most of the places.
Anyhow, the below would be the more appropriate cultural division of America.
Note that less than half of Colorado would really be deseret, though Idaho is sort of in-between North-West and Mountain-West.
That's pretty accurate IMO, Iori.
The only suggestion I'd make is that southern Idaho and SW Wyoming should really be in Deseret.