The version I learned in grade school should probably predate PP&M, but I am not sure. It would have been somewhere in the vicinity of 1960-1963.
Here I sit on Buttermilk Hill.
-------------- and cry my fill.
-----------------------------
Johnny's gone for a soldier.

Oh, my baby oh, my love,
Gone the rainbow gone the dove.
Your father was my only love.
Johnny's gone for a soldier.

Shool, shool shool aroon.
Shool a rack shack,
shool a bobba coo.
-------------------
Johnny's gone for a soldier.

There are some lines I can't remember and the rest is the recollection in my 50's of words I may have misinterpreted at 11 or 12. The word Buttermilk is what I remember, but may have been corrupted by later hearing the PP&M version. Does anyone esle remember this or any thing similar?