[Firebird]

I don´t think driving in Japan is to bad, but roads around Osaka/Kobe are very different from Hokkaido.
Parking can be difficult in Kyoto itself and a bit pricy in touristy areas.
I´d recommend to go by train because you´re covering quite short distances and i think its less of a hassle going by train than by car ( both places you want to visit should be connected by a more or less frequent train).
Renting a car can be a good experience outside the city areas but i wouldn´t recommend it in your case.