JCCA has been planning to piggyback on a local classic car company's rally. As far as I can tell, the only differences between their rally and the JCNA requirements is that they don't give the times, only mileages; they don't give the locations of the checkpoints; and they don't have a test run prior to the rally.
We can handle the last item, but wasn't there a discussion of allowing rally scores from events similar but not exactly structured as JCNA rallies? I couldn't find anything in the rules.