Fukuoka to Kurokawa Onsen

Good morning,

We will be staying at the Plaza Hotel Tenjin on the evening of the 17th of October and following our stay, we plan on going to Korukawa Onsen from the 18th to the 20th and return to Hakata Bus Station.

Could you let us know what you would recommend for transportation to Kurokawa Onsen from Fukuoka on the 18th?

The following bus line seem to provide transportation from Nishitetsu Tenjin Bus Center which is close by to our hotel to Kurokawa Onsen. Can we simply schedule our bus tickets on our arrival in Fukuoka for a next day departure?
http://www.nishitetsu.co.jp/bus/highway/gb/guide/kurokawa.htm

I would be grateful if you could provide us your recommendation on this matter.

Sincerely,

Jaber