My best option?

Hi,
I'm traveling to Japan soon. Looking forward to that! But I have a question; Is it better to buy singel tickets or a regional pass for my journey?

My itinerery is as follows:

Day 1
From Kyoto to Kii-katsuura (staying 1 night)

Day 2
Fron Kii-katsuura - Owase (staying 2 nights)

Day 4
From Owase to Nagoya, and furthur on to Owari-Seto (staying 1 night)

Day 5
From Owari-Seto/Nagoya to Tokyo.

I appreciate your help and hope to hear from you soon!
/Maria