The Japan Rail Pass Calculator on this website can give you a good idea if a pass pays off, but it doesn't always give you the full picture, if that makes any sense. So for example, my next trip to Japan I am arriving on Wednesday and immediately going from Narita to Kyoto. I'm spending 4 nights in Kyoto and then going to Nara Prefecture, before slowly traveling through Mie Prefecture on private lines and arriving in Nagoya some time on Thursday to take the train to Tokyo. I then want to on Sunday go up to Morioka rent a car travel around, eventually take the train down to Koriyama, rent another car, and then go Koriyama back to Tokyo before leaving Japan. If you put in all those train fares in the calculator, I get that a 1 week, 2 week or 3 week pass would pay for itself. However, if I pay out of pocket for Narita to Kyoto ~16,000 yen, out of pocket for Nagoya to Tokyo ~10,500 yen and buy a flex 5 day JR East pass 20,000 yen I get a total of 46,000 yen which is less than the 3 week pass of 59,350 yen which is what I would need to cover my 17 day trip. Plus, since I don't have the pass I can take the more frequent Nozomi and get to Kyoto earlier.
So going back to your itinerary, the majority of your expensive travel is between Day 2 and Day 8. you're going to be taking buses to Takayama from Kanazawa and from Takayama to Matsumoto.
So assuming you take a limited express from Matsumoto to Nagano with a reserved seat and then the shinkansen from Nagano to Tokyo with a reserved seat you're paying 39740 yen with a 1 week pass. A 2 week pass won't solve the issue of needing transport to and from Narita because with the extra 3 days you have 15 days in Japan. So one of your NEXs wouldn't be covered. You can use the private Keisi line or even a limo bus, I have a few friends who swear by the buses. They tend to stay in hotels serviced by them.
If you don't extend the trip or cut out the trip to Hiroshima that really alters things. I think on your extended itinerary you are in Japan just long enough to not be able to use this discounted NEX round trip:https://www.jreast.co.jp/e/pass/nex_round.html?src=gnavi
, since it's only valid 14 days However, if you plan your trip so you are just in Japan 14 days, you can use this extremely good deal where it is 4000 yen round trip on the NEX.
With your original 11 day itinerary it would depend on whether you plan to take the train from Takayama to Toyama to Nagano or take the bus from Takayama to Matsumoto to the train from Matsumoto to Nagano when I would start my pass, but again I would probably just get a week because you're looking at ~39000+the 4000 vs. 46100. I think technically Takayama to Toyama to Nagano all by train is faster, but the trains between Takayama and Toyama are very infrequent and if you miss the train downtown Takayama near the station is pretty dull.
You might want to look at this bus pass: http://www.alpico.co.jp/access/ticket/pdf/panf701
.pdf it's 5500 yen for Kanazawa to Shirakawa Go to Takayama to Matsumoto. I really liked Matsumoto. I wish I had more time there last trip.