Good info Kayaktom, I always wondered why this site was not shown on the map. We stayed there many years ago and wondered if it was supposed to be closed but there was no signage and it didn't look closed.
We loved the campsite for the exposure to the lake by the firegrate, found 3 good enough tent pads for small tents and found the sunrise views amazing and the small island out front made for some nice photo opportunities.. Not to mention the fishing from shore. It's a great but smallish site and as you said, convenient for a daytrip to Pine and Johnson Falls.
My tent site and the living room of the campsite
Morning view of the island out front
Sunrise view to the east
The upper falls at Johnson Falls, the one that some folks miss cuz they don't know it is there.