Tottori Prefecture self drive?

Hi,

I am planning to visit Tottori from Osaka on a Kansai Wide Pass. Thinking of going Okayama first then self drive to Tottori since I understand there are no toll charges in Tottori Prefecture and the car rental charges is actually quite afforable . However, will like to ask expert if it is better to just get Sanyo San Pass In Pass and take train directly from Osaka.

My self drive itinerary is as follow:

Day 1 : Okayama to Tottori Sand Dune & Sand Museum - Tottori Market - Kannon Temple - 1 night stay
Day 2 : Tottori - Kurayoshi - Conan Street - Pear Museum - Sakamiminato - 1 night stay
Day 3 : Sakmininato - Okayama Toy Kingdom - Okayama - 1 night stay

Travelling with a 7 year old boy and we are not actually a manga fan therefore not sure if we really want to go al the way to Sakaminato. Just trying to maximise the car. However, since both Conan street and Sakaminato is just next to the train station therefore, undecisive if a car is really necessary.

We will be visiting in early June will Tottori be ideal since it might rain or we should try Shikoku? Trying to go for an area with more kids activities

Sorry if Its abit confusing for my question.

Thanks in advance

I really don't see the point of doing all that driving. It only really makes sense if you are going to some isolated place that is either poorly served by trains/buses or not served at all. From what I can see, you don't really need a car - and you can use a JR Sanin Okayama Area Pass which is not expensive at all.
https://www.japan-guide.com/e/e2361_sanin.html
At worst, you can get a car once in Tottori.
You know what suits you best, but if I were in Tottori, I'd go to see the Uradome Coast east of Tottori City in Iwami.
https://is.gd/PngU9a
https://www.tokyocreative.com/sights/5472-uradome-coast
Much more interesting than a pear museum, but maybe you really love pears even more than I do. It's a good walk for a 7-year old, but there are so many places to stop and just watch the waves crash ashore.