The Harrowed Realm is pretty cool! Especially if you've played the
1st edition module that not only inspired this chapter but the whole adventure path. Unfortunately, outside of the scripted locations, there's not a ton of detail on how to run it. It's not nearly as bad as Katapesh in Chapter 1, or any of the popcorn locations in Book 1, that really feel like you need 7 other books and hours of research just to set the scene, but I think this scenario would benefit from a little more connection between those disparate threads.
And there are hints in the module that it originally was going to be! Page 49 says "three events will take place as they travel. The first of these, Event 5, takes place automatically the first time they arrive in the Harrowed Realm." James Jacobs confirmed that these events were incorporated into the set adventure locations, and this line was meant to be cut but was missed. On the upside, this probably made those locations cooler! On the downside, it makes the Harrowed Realm feel more static in a way I don't love.
So, today we'll be going through this chapter and the 1e module to better orient ourselves in the Harrowed Realm and help breathe some life into it!