itinerary help : Osaka-Kansai Mt Koya

Nara, Takayama, Shirakawa-go, Kanazawa, Kyoto, Hirishima, Miyajima, Himeji,back to Osaka-Kansai

We are two couples Would it make sense to rent a car for the first part of journey of about 10 days ending in Kyoto.
then proceed to Hiroshima, Miyajima, and Himeji, by train
before returning to Osaka Kansai.
If not what would be the most logical itinerary buy train and/or bus ?
if so any recommended rent a car office with an english website ??
many thanks your help,
Michel.

for some of the places on the first part have a look at: http://www.japan-guide.com/e/e4208.html
Nara is easily accessible from either Osaka or Kyoto (these three cities are the heart of the Kansai region)
I am a bit confused by the rest as I don't see anything about Mt Koya. As far as I know access to Mt Koya is easier by Nankai trains from Osaka-Namba then a cable car then a bus (there is a special
tickets for the 3). Travelling by car from Kyoto to Takayama etc. may be cheaper for 2 couples than trains and buses but it depends how comfortable you are driving on the left side of the road on country roads that may be narrow at times. parking is also a problem as many parkings have ticket machines that aren't too easy to understand. To go to Hiroshima and Himeji is easy by car. For Miyajima one has to park on the mainland for the duration of the visit to the island.. there is a JR West Sanyo pass at yen 20 000 per person for 4 days. It starts at Osaka and serve points west of it, all the way to Fukuoka.

Thank you Monkey see , may be it was not clear ..
We land in Osaka and we like to take in :
Mt Koya, Nara, Takayama, Shirakawa-go, Kanazawa, Kyoto, Hirishima, Miyajima, Himeji,back to Osaka-Kansai
I wonder what would be the best itinerary , and since I have see in other forum that
a self drive car would be easier for Takayama, Shirakawa-go, Kanazawa, I was wondering it it mad sense to start with a Car from Kansai Airport then go south to Mt Koya , then Nara , and upto Takayama ,Shirakawa-go, Kanazawa, then drop back the Car in Kyoto.and continue by train.