This reminds me of my favorite TSR regional supplements of old, which provided brief, captivating paragraphs about local geographical features (lakes, mountains, wetlands) for Wardens to build upon. Some provocative ideas here: sea monsters lurking in the depths, abandoned mineshafts, sentient tree groves, carnivorous fungi, and so on. It also contains a useful microclimate system with some unique weather options. A type of fog called pogonip--which causes frostbite but can also mesmerize hapless travelers with the eerie music it makes--is a particular favorite of mine.