Paulj: The directory doesn't really cover as much on interstates; mostly secondary highways. Yes, there are descriptions in Yellowstone: Craig Pass, Dunraven Pass, Sylvan Pass.
There's usually too much description to directly quote a highway out of the directory. In describing routes I just pick the main grades. I'm sure many do the same without directly quoting word for word.
It's well worth purchasing if you drive mountain areas a lot. Even though we drove the same highways many times we still referred to the directory to refresh our mind on what's ahead.
