Okay, I can now get the sync operation running, but...
1) that one calendar (out of 21) just refuses to come down to iCal.
2) and, another entry I modified the title of in iCal, in a separate
calendar - the modification did not make its way to Gcal; in fact, the
local iCal title reverted to the earlier-synced version from Gcal.
And I'm still getting category names listed as unconfirmed invitees.
Such a shame. I was going great guns :(