Regarding the sauna, use two long sticks to act as tongs or holders of the hot rocks as they come out ot the fire.  No one gets burned.  About thirteen years ago I came across a makeshift sauna built on a great island on Kawnipi.  The framework of the sauna reminded me of my Eureka Wind River tent.  All you had to do was tarp it and there was a small depression for the rocks.  This was fifteen feet from the waters edge so a cool dip was near by.  This island also had the most ingenius crapper.  Two lengths of pine trees about 7' long were twined about two and a half feet off of the ground between two other trees.  All the bark was burnished off and the seat area had duct tape, so no splinters.  Along with the great fire pit this was a great star site.  But I digress .8-)