I myself would try researching where & how the homes were set up where the buggies would pull in If there were any large trees where people would picnic under, use for shade, mayb gardens,& because u had said the 40's might be an old privy out there to, once you have researched how it all was set up I would section it off into 4 squares, then grid each one off 1 way then go another. Perhaps even do it in layers sort of peeling back the years ya know get rid of the trash on top 2-4" then after u get those go for the deep signals & really clean up,
As of research
-library
-town Hall
-historic map works
-sanborn maps
Theres much more out there hope this helps some good luck, & nice finds so far hh