"Was surprised that Rick didn't cover more of the area. "
There are two factors with this:
1) Rick doesn't try to cover any country comprehensively. He covers what he considers the prime destinations, for first time visitors from the US, with limited time, and "standard" interests. For instance, a dedicated hiker would need to supplement his Alpine listings, and an art historian would find his museum listings inadequate.
2) For his Italy book, a staff member who posts here has specifically said that his publisher will not enlarge the book any further, so he cannot add more information about Italy, even if he wanted to. If he enlarges the section about one Italian destination, he has to shrink a section somewhere else.
So, I always supplement Rick's books with others. It's interesting that in this case, Laurel says she hasn't found other good books for this area (presumably, living in Italy she could use Italian books, not just English language ones).