I am trying to enter a cell that I have been working on the past 2 days. about an hour ago I stopped being able to CoC in. After that I tried entering through the door connected to another part of my dungeon. The game doesn't seem to even attempt to load the cell in either case. As soon as I hit Enter witht he console, or as soon as I activate the door, Skyrim crashes. My cell is 100% Custom, is fully navmeshed etc. Any ideas?

It was working, and now it is not. It seems plainly obvious that you did something that is causing it to no longer work. Roll back to an earlier version, undo the changes you made, and see if that fixes it.

Yea... Been thinking that. But, I didn't change anything. At least I don't think I did. XC Is there somewhere in data details were I can see changes in the ORDER that they were made?

If only that was possible but it isn't.

Still not working. Tried deleting the last thing I was working on: Some ambushes I added. Deleted all of them, still no success. Then ran another NavMesh check. Apparently there were errors that it didn't tell me last time. I cleaned them up, still CTD on cell load.
Dang... I have no clue. I even deleted the ENTIRE Navmesh. Cell still won't load.

Go to your Skyrim folder, there into the Backup folder. It contains your last worked on mod-esps. Copy them to another directory and try them one after the other to find one that works and compare that one to your current not working one.

Are there some general things that people know causes CTD?

well. Reverted to my backup.