Zao-san Transportation

First, take the Yamagata Shinkansen to either Yamagata or Shiroishi Station. There are local buses from these 2 stations. There's a direct bus from Sendai JR Station but only 1 trip a day (Cost = ¥2250 each way).

Bus Schedule:

From Shiroishi To Katta Peak:
Depart 9.43, Arrive 11.15.
Depart 10.57, Arrive 12.28.
Depart 12.43, Arrive 14.14.

From Katta Peak To Shiroishi:
Depart 12.03, Arrive 13.39.
Depart 13.40, Arrive 15.15.
Depart 15.20, Arrive 16.56.

From Sendai To Katta Peak:
Depart 8.30, Arrive 10.30.
From Katta Peak To Sendai:
Depart 14.40, Arrive 16.46.

To get to Zao Quasi National Park & Okama, the more adventurous way is by the Zao Sanroku Ropeway to Juhyo Kogen (the location of Snow Monster) & then by the 2nd ropeway to Zao Jizo-o Sancho Station at 1661 m.

Cost = 1200 Yen.

If you have lots of camera gears & belongings, I don't suggest going by this way. Check out the pix & you'll know what I mean. For those who have height phobia, do not go by this way!