one month in Japan - which JR pass is suitable?

Hi

A group of 4 of us are coming to Japan for one month and looking forward to it!
Can you suggest which JR pass to get and when we don't have the JR pass, what tickets/pass should we get?

Originally I was thinking of a 21 day JR pass starting 17th April to 7th May.
So then #2) bus to Fuji Five Lakes, #3) bus to Hakuba

1) 9 April - Arrive into Narita Airport
2) 11 April - day trip from Tokyo to Fuji Five Lakes (Kawaguchiko)
3) 12 April - travel from Tokyo to Hakuba
4) 17 April - travel from Hakuba to Nakatsugawa station (to walk the Magome/Tsumago trail)
5) 18 April - travel from Nagiso station (staying the night in Tsumago) to Kyoto
6) 18-28 April staying in Kyoto - we will definitely want to visit the following places as day trips: Hiroshima, Miyajima, Arashiyama, Nara, Ise-jingu, Himeji
7) 29th April - travel from Kyoto to Tokyo
8) 29 April to 9 May staying in Tokyo - we might do a couple day trips: Hakone, Nikko, Takayama, Nagoya, Mitake-san, Kamakura

Your help and suggestions would be much appreciated. Thanks.