Japan Rail Pass needed?

Hello,

Myself 30 and my partner 30 will be travelling to Tokyo on the 19th April 2019 and have the below itinerary planned out. We just need a little help with figuring out the best way / Quickest / Cheapest way to get from A > B.

As it is golden week during the last week of our stay is it also better to prebook all travel in advance?

Any advice on the above would be greatly appreciated and also if you have any must-dos for the below destinations ;)

Thursday 18th Flight In
Friday 19th Tokyo (IBIS) IBIS Hotel
Saturday 20th IBIS Hotel
Sunday 21st IBIS Hotel
Monday 22nd IBIS Hotel
Tuesday 23rd Kyoto - Granbell hotel
Wednesday 24th Granbell hotel
Thursday 25th Granbell hotel
Friday 26th Granbell hotel
Saturday 27th Granbell hotel
Sunday 28th Hiroshma Grand Prince
Monday 29th Grand Prince
Tuesday 30th Grand Prince
Wednesday 1st Kanazawa Mitsui Garden
Thursday 2nd Nagano -Hotel Metropoliton
Friday 3rd Hotel Metropoliton
Saturday 4th Kusatsu - Yubatake Souan
Sunday 5th Yubatake Souan
Monday 6th Tokyo Book and bed
Tuesday 7th Book and bed
Wednesday 8th Book and bed
Wednesday 8th Flight Out

We just need a little help with figuring out the best way / Quickest / Cheapest way to get from A > B.

Your long distance travel (Tokyo-Kyoto-Hiroshima-Kanazawa-Nagano-Kusatsu-Tokyo) will be 14 days and costs about 50000 yen so JR Pass 14 days will be suitable. I recommend to buy 21 days version since you will be staying in Tokyo for 7 days when you can do some long distance side trips to see cherry blossoms in Tohoku area or even in Hokkaido (Hakodate and around).

As it is golden week during the last week of our stay is it also better to prebook all travel in advance?

The most busy days of Golden Week in 2019 are 26th evening/27th April morning from Tokyo, 2nd evening/3rd morning May from Tokyo and 6th evening to Tokyo. So I think there would be no big problem for your itinerary, but you should always book in advance to avoid separate seating.

Any advice on the above would be greatly appreciated and also if you have any must-dos for the below destinations ;)

Basically I like your itinerary since you will stay multiple nights for eace place. This will make your travel flexible. In fact Japan is rainy country so you might have to change your plan on the day of travel. How do you plan to go to Nagano from Kanazawa? Via Alpine route? If so you might better have plan B.