Different services with or without JR

Hello,
I am planning my travel to Japan for this autumn and to find out if JR Pass is the right solution for me I would like to know which services would not be included in the JR pass. I remember having a JR pass last time (10 years ago) and using for the Shinkansen and the Tokyo metro but not the buses in Tokyo or a train from Nara to the countryside near Nara (to a friend's house). I am most likely to travel quite touristic destinations this time but I don't want to pay over £1100 for two 21-days passes (it's two of us) and find out that we still need to pay a lot for local transportation. How can I find this out?

Thank you,
Silvia