One of the best documented "Solitary" lives was that of Richard Proenneke (https://en.wikipedia.org/wiki/Richard_Proenneke) who lived by himself for 30 years in Alaska's Twin Lakes Park.
His self-documentaries Alone in the Wilderness (Parts I & II) and The Frozen North are some of the best and most soothing videos i have ever seen. See also his book One Man's Wilderness.
You don't need Religion/Mysticism/Higher Calling to love Solitude and want to live in an Natural Environment.