I've been onto Hyperdia doing some costings and I am still undecided whether a 14 day or 21 day JR pass is the most cost effective. Itinerary is a follows (accommodation has been booked):
22/3 Day 1 - Evening arrival at Narita. Activate JR Pass and book fare to Kyoto. Overnight Narita hotel using hotel shuttle bus
23/3 Day 2 - Narita Airport to Kyoto (4 nights)
27/3 Day 6 - Kyoto to Mt Koyo (overnight)
28/3 Day 7 - Mt Koyo to Osaka (2n)
30/3 Day 9 - Osaka to Hiroshima (3n, including day trip to Miyajima)
2/4 Day 12 - Hiroshima to Kanazawa (2n)
4/4 Day 13 - Kanazawa to Takayama (2n, Nohi bus via Shirakawa-go)
6/4 Day 15 - Takayama to Matsumoto (1n)
7/4 Day 16 - Matsumoto to Tokyo (5n, Akasaka)
12/4 Day 21 - Akasaka to Narita, evening flight home.
The 21-day pass fits nicely if the pass is activated on Day 2. I am unsure if we will do any day trips out of Tokyo during the five days we are there. We are travelling as a couple.
Thankyou.