If you look for more destinations on your road trip through the remote south of the Kii Peninsula, then put Maruyama Senmaida on your must-go places to visit. Located in a difficult to get to area in the south of Mie Prefecture, the best way to travel to this location is indeed by rent-a-car, camper van or by your own car, in case you live in Japan. Your access is from either Kumano Town in Mie Prefecture or from Hongu Town in Wakayama Prefecture. From there you drive along mountain roads with fantastic views to get to Kiwa Town. Kiwa is called a town but it is more like a big village in the middle of no-where. This is the location of the Maruyama Senmaida.
Rice is planted in mid-May and harvested in September. The best time to visit this place is during the time that the rice is growing in the rice paddies. During other times of the year it is fine to come here too, as you would see the terraced fields in any case. However, they look better with the young rice seedlings just planted or the yellow stalks of rice just before the harvest.
While Kiwa has some facilities where you get some food and drinks, there are not many and they are not near the Maruyama Senmaida. Hence, bring a bento box and some drinks with you and then enjoy the view while having a picnic by the fields. Some farmers might be selling fruits and vegetables near the fields.
Terraced rice fields are a scenery that we now associate with places like Bali or Thailand but in Japan in the old days there were terraced rice fields too. Many have fallen into disuse and disrepair, and the few left are becoming quite famous now. For example, the Sakamoto Rice Terraces in Miyazaki Prefecture or Shiroyone Senmaida on the Noto Peninsula.
If you look for the old Japan, then a visit to the Maruyama Senmaida is highly recommended.
Out in nowhere, your best option by far to get there and to move on is by car. It is a 40 min drive by rent-a-car from Kumano City in Mie Prefecture. You can also drive there from Shingu City or from Hongu City in Wakayama Prefecture. Why not combine it with a visit to Totsukawa Village on your road trip across the Kii Peninsula.
Alternatively, there is also a public bus from Kumano City run by Mie Kotsu. You need to get off at Senmaida/ Toritoge-Iriguchi bus stop and walk for 30 min uphill to get to the rice fields. If you get back on the bus and go to the terminal Seiryu-so Onsen, you can stay at this onsen hotel and enjoy a hot bath after walking around the rice fields. The bus leaves daily from Kumano City, opposite the train station at 11:25am. The journey takes about 1 hour. Please check the bus time table, as there are not many busses running over all, or they run just on weekdays, or just on weekends and holidays.