I am sorry I reply to you so late.
There are lots of campgrond in Japan.
I think that every camgrounds are very expensive to stay.
And there are lots of parking area. We call it "Michi-no-Eki", which means "the station of the road".
These are very convinient. It's free!
I will start to go camping with my casita.
I will upload the diary and photo about the campgrounds in Japan on my web site.
Please come my web site, Kieth.