Iliana, I was setting up the map region for Rimmen, and checked your Orcrest region to see how you configured it. When right-clicking on any quad of the Orcrest region (2, -22 to 5, -25) and selecting 'View world here' the CS sets me deep below Orcrest (z -30000). Theres a whole forest of vanilla trees down there, seems it needs some cleanup.
If they're all at -30,000 on the Z coordinate, then there's nothing to worry about. Those will be vanilla objects which aren't wanted. Since deleted things can cause CTDs on exit, it is better to disable unwanted vanilla objects instead. But if you just disable them, then they'll still appear in the CS and that makes a mess when you're trying to work around them. So to get around this, a modder can disable them and drop them to Z -30000. TES4Edit has an option to automatically undelete all deleted objects, disable them, and drop them to Z -30000, so clearly Iliana has used TES4Edit to keep things clean and tidy. Very wise