Bicycle travel · Slovenia

We're planning to cycle through Slovenia on touring bikes from July 14th to August 14th. We're used to camping, but I get the feeling there are large areas without campsites. Is wild camping allowed? If not, is it easy to stay with locals?

Could you tell me about the must-see spots in Slovenia? I'm thinking of finishing in Istria, at a seaside campsite to relax and enjoy the sea. Is it pretty quiet there?

Thanks so much, Mireille.