What a ride! Hope to explore some of those climbs someday!
Downhill on some of those roads would be scary in the wet.
Downhill on some of those roads are scary when dry. :-) I didn't make downhill segments on any of them. The "Myodokai Climb" is a big wide fantastic descent, but it's on the grounds of a religious organization and I don't think it's appropriate to ride too quickly there.
Geoffrey, there are still a bunch more further north, some that appear to be much, much longer/steeper.