Keith:
Thanks so much for your prompt reply. This is what I was looking for!
I'd like to add from my experience here (for those who may come across this thread in search of the same) that to completely restore everything to default you need to first reset the base, then reset the handset.
If you rest the handset first, then you will need to re-register the handset to reset the base. At this point the phonebook will synch and reload the directory from the base back to the handset. Clear the base first and then clear the handset.
Best,
Derek