There is a parking at the beginning of Pivonice village. Continue on a red trail approx 0,6km uphill. There are 3 touristic shelters, big meadow (space for more tents) where it suppose to be possible get with car (I don’t know how).
Big fireplace is located under the castle – one tent can fit there. It can be bit crowdy in a summer but I think that tent should not be problem at all. We slept there in a winter and nobody there 🙂
There are some hidden places in a ruins that can provide nice place for bivouac and can provide protection against rain.
Great spot, highly recommended 🙂