Our itinerary starts in Kumamoto (flying in from Seoul) and we will spend a night or two there before heading out to Takachiho for a day trip. Instead of returning to Kumamoto, we'd like to spend the night at Kurokawa Onsen for two nights before heading to Fukuouka. We haven't had any luck finding an efficient bus route that takes you from Takachiho to Kurokawa. Is taxi our only option?