Iriomote itinerary

I'm planning on spending a day on Iriomote Island in January.

Arrive at Ohara port and take a cruise along the Nakama River. Walk (is this possible) to Mihara to catch a buffalo cart to Yufu Island. Walk from Mihara to Uehara port for a cruise down the Urauchi River. And then back to Ishigaki.

Is this doable?

If I have to choose a river cruise, which one is better?

Thanks!

It is over 10 kilometers from Ohara to Mihara and more than 20 kilometers from Mihara to Uehara. It will take hours to walk these distances.

If you have only one day, I recommend to concentrate on just one of the two rivers. I have only been to the Urauchigawa and have very fond memories.

Clearly too far to walk. Would I be able to incorporate all of those things if I used the shuttle buses? Or, should I just stick to the Nakama River cruise and Yufu Island? Is there anything else to do on Iriomote? I figure I'd start my day early, but with doing that, seems like I'll have a good bit of time left. Are there any beaches? Or should I check out Kohama or Kuro islands?