Worth it to get 14 day vs. 7 day?

Hello,

We will be traveling to Japan on March 6. Our itinerary is as follows:

Arrive in Tokyo on March 7-11
March 11-12 Takayama
March 12-15 Kyoto
March 15-17 Osaka
March 17-18 Miyajama (Hiroshima on morning of the 17th)
March 18-20 Tokyo

I was thinking that because we may only activate the JR pass on the 11, that would cover us until the 18, and we would just need to purchase one way from Miyajama to Tokyo. Would it be worth getting a 7 day plus one way to Tokyo from Miyajama or would we be better to get the 14 day?

Thanks!