Park in Zrnovci and walk across this bridge:
and up the river to the St. Tomas Monastary Geocache (full directions at St. Tomas Monastery Geocache). Notice the red mule shoe marked "20" on the trail.
Continue ten minutes to the mule shoe marked "30" and another minute to the mule shoe at this spot:
continue downward, across the hill, following the small red paint dots and red mule shoes to the river. There you will find a waterfall with a swimming hole:
a heart shaped table 
a stone throne,
above is the cave with a woodstove,
and two beds.
A sleeping pad is under the upper bed:
sometimes there will be lots of friends:
The cave is free, on a first come-first served basis. Contact Blagoj Danev for any needs in the Zrnovci area.