Does anyone know how to access the *.kmz file which can then be used on Google Earth as an overlay for each state?

An example is found on GCHANH - California DeLorme Challenge (Northern) (United States). Under the description under "Tools/Downloads" is a file called https://www.dropbox.com/s/bicryfjyvssbjy2/NCalDeLormeGrids.kmz?dl=0 which can be loaded on to Google Earth. I would love to be able to use this for other DeLorme Challenges but not sure how to find them.

I wouldn't be surprised if that were a file the cache owner (or the original CO, given it's been adopted) put together themselves to assist cachers, possibly even before the PGC checker system was available. You might want to send them a message to ask.

The file can be found at
https://sites.google.com/site/rowd0001/delorme-kml-files

Thank you! This is perfect!