Well , 40 years old is not that old but that is 40 years of things lost and who knows what from before it was built. I would say get under that old wash line and around the driveway . As for settings I would be looking for coins and rings .
I think it's most impotant to take your time and enjoy the hunt
Dig the high tones and anything else you think is a nice solid signal . Remember that a target that you cN still hear with your coil a foot off the ground is best left alone . And there may also be underground power running to a smAll shed or a front yard light post . Best of luck and just enjoy the day.
Also the folks letting you hunt there property may know of older properties or family member homes . Let them know the older the better and often a best find at a permission is another permission be it a neighbor or whatever
Looking forward to your hunting report . , Dew