The easiest way to find these URLs is to go to the Google Search Coverage for 404s and fix those.
I've got a spreadsheet that tracks the URLs I'm aware of, and marks them out as they're fixed.
It's super helpful when getting a usable URL to use the URL Encoder/Decoder.
With VIP Go, the redirects are so bad because of the lack of regex for end characters, so I don't really know yet what to do about those.