Note: I feel obliged to say that by this time your best deal is likely to get just a JR pass. Your trip from Tokyo to Kyoto costs 18,000 yen, while your trip from Osaka to Hiroshima costs another 10,000. If you also need to return from Hiroshima to Tokyo, you should seriously consider a JR pass. If you have a JR pass, you do not have to worry about anything.
You can easily reach Tokyo via Kyoto to Nagano and Kanazawa. Here is the desired route:
Tо̄kyо̄ — via Shinkansen — Nagano — via Shinkansen — Kanazawa — via the Hokuriku Main Line, the Kosei Line and the Tо̄kaid®̄ Main Line — Kȳ̄to
If you can read Japanese, use a ticket machine and buy one base ticket, You can select the desired route. Then buy all the required limited express tickets while you go. Usually I do that before I go by train. The limited express train operating between Kanazawa and Kyoto is the Limited Express Thunderbird (サ ン ー ー),
If you can not read Japanese, it is best to show this to the person in a ticket sales window:
東京 — 北 陸 新 幹線 — — 長野 北 新 金 金 京都 京都 京都 京都. 長野 北 京都 京都 京都 京都 京都 京都 京都 京都
Your basic ticket should be printed as follows:
由: 幹線 · 長野 · 新 · 金 沢 · 陸 · 道
Note that you do not have to list all the waypoints. Since your ticket is destined for a very long journey, stopovers are only allowed if you are not getting off within Tokyo or Kyoto. Stopovers, however become If you have a restricted express ticket, your ticket will become invalid.
Your second itinerary will work very well. It is 337.8 km from Osaka to Hiroshima. According to JR rules, your basic ticket is valid for exactly 3 days.