Having made it safely back to Nago, the next morning I set off southward along the coastal road to try a different way of getting back to the eastern coast to continue my ride south. This is the infamous Highway 58; it really doesn't look so bad in this photo. Rest assured that when you get closer to Naha it's wall to wall traffic, including many trucks: not a fun ride.
Eventually I chose a short road that would get me to the eastern coast in a mere 6 km, with only a steady but relatively short climb. This is an aerial view from one of the bridges, looking directly down at the lush tropical scenery below.