Where might one find each, so at least possible? (6,3,6,2,6)

'least possible?' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'where might one find each so at' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'un' (northern English dialect form of 'one') and 'un' is located in the answer.
'each' could be 'ea' (abbreviation) and 'ea' is located in the answer.
'so' is within the answer.
'at' could be 'on' (location) and 'on' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?