Lovecraft is, I think, best known for his adjectives. More than Cthulhu, even than the Necronomicon, Lovecraft distinguishes himself by a flood of adjectival description for every object, person, landscape, and sensation. The effect is hypnotic, causing the reader to feel immersed in the actual location. I have always thought of Dunwich's adjectives as grubby, ramshackle, and decayed; for Arkaham, I think of dark, secretive, ancient, and haunted. After reading the Kingsport sourcebook, I have an even stronger feel for that location: quiet, contemplative, shrouded in mystery. The rhythm of wave and tide pacing the flow of time from one generation to the next. The ubiquitous mists sheltering the town from the march of progress, allowing memories to accumulate. It seems like the perfect location for an ancient mystery to resurface.
One excellent aspect of the Lovecraft country books is the inclusion of at least some of Lovecraft's original stories dealing with the town - that is why we're here, after all. Kingsport's stories are "The Strange High House in the Mist" and "The Festival". I would have also liked to see the inlcusion of "The Terrible Old Man" as well as "The White Ship", but that might conceivably be giving away too much.
There follows some short sections on what life is like in Kingsport, the history of the town, and the low-down on the local cult (which I thought was pretty good). Afterwards is the standard breakdown of the locale into neighborhoods/regions. Each section lists any interesting residents, locations, and any useful items or information located there. I find this to be an excellent inspiration for ideas. If you are not completely into one-shots, an excellent long-term idea would be just to explore the town, investigating history and mystery. I know that my gaming group actually likes this sort of thing better than epic quests and whatnot. I also really like the town directory, sorting people, places and things into categories for easy reference with their page number.
About half of the book is scenarios. There is a short section on how to use character dreams during gameplay and then 3 scenarios. I really can't say much about them without being a spoiler. I can say that "Dead in the Water" has a lot of material and looks very intense and draws out many of the unique characteristics of Kingsport.