Miyazaki to Sekino-o falls

I am planning to stay a night at Kirishima Iwasaki Shrine and another night in Miyazaki . Plan to do a day trip to Sekino-o falls.
Any advice whether I should go from Kirishima or Miyazaki.
And can i make full use of my JR pass on this day trip ?

Any advice whether I should go from Kirishima or Miyazaki.

The falls are located just about halfway between Miyazaki and Kirishima. It would be most efficient to visit them along the way.

And can i make full use of my JR pass on this day trip ?

You can take JR trains to within about 6 kilometers of the waterfall, but from there you would have to take a taxi or bus, which is not covered by the Japan Rail Pass.

There is a bus, which operates between Kirishima Jingu and Miyakonojo Station, which stops at the falls along the way. It is the easiest way to visit the falls by public transportation, but it is not covered by the Japan Rail Pass.

Thanks Uji-San
Apologies for being undecisive. If I stay in Miyazaki , I could take JR to Aoshima station then take a 40mins bus to the fall. How often does this bus operate? Or is a website that I can check the timetable ?
OR I could do Ebino Kogen, Kirishima Shrine together with the falls as a Day trip from Miyazaki?

If I stay in Miyazaki , I could take JR to Aoshima station then take a 40mins bus to the fall.

It seems to me that you would better take the train to Miyakonojo and then the non-JR bus to the falls.

How often does this bus operate?

I think five times per day. It is the orange line on the following map:
http://www.japan-guide.com/g/4626_bus.gif

OR I could do Ebino Kogen, Kirishima Shrine together with the falls as a Day trip from Miyazaki?

Note that there is no public transportation to Ebino Kogen outside of weekends, expect in May. Apart from Ebino Kogen, a day trip from Kirishima to the shrine and falls seems feasible.

It seems to me that you would better take the train to Miyakonojo and then the non-JR bus to the falls
How frequent is the non-JR bus ?

5 round trips per day.