Japan 08th to 20th of Octuber

Hi how are you??
My boyfriend and I are going to Japan from the 8th of October to 20th of October. We are arriving to Tokyo and we depart from Osaka to continue our trip to China.
Our idea so far is stay in Tokyo for 4 days and then keep going southwards visiting Kioto, Nara and finishing in Osaka (maybe we can add an extra place to visit) We have read different opinions about the JRPass, but it always says that it depends on the route and the itinerary, so can you please help me to figure it out if it is convenience for us ??

Thanks in advance

Nicole