I found several extremely knowledgeable coaches back around 2004-2005.
All of these guys were really strong and they all trained in garages, parks, back yards, etc. None of them trained in gyms!
One if the first training resources I ever got my hands on was Zach Even-Esh’s
Underground Strength manuals http://tinyurl.com/bjjmnlq
Almost 9 years later, I still refer back to them.
I market Zach’s manuals because I believe in his training, and use it myself.
The Cave 