So I'm in progress on a map that's probably gonna near the 4,000 limit. I really, really don't want to do "Territory_ID#" on every individual one.

I know it's been talked about countless times before and there at least used to be an extension for it, but I can't find it anymore. Does it still exist? Does a new one exist? Or am I gonna have to do this the hard way?

You can do Replace All on properties of the object.

1. select all your territory paths (Ctrl A on the entire layer if you seperated those)
2. use Ctrl H to bring up the Find & Replace tool
3. make sure you tick the checkbox for searching in objdct properties
4. replace all "Path" with "Territory_"

If you need more help, feel free to ask and I'll give some more details and/or pictures when I'm at my pc again.

You're a damn lifesaver. I always knew I liked you.