Well just an old Scarecrow, but something with your diagram I see. You have a cellar in one spot, and a fireplace in another? Two buildings. Way way back, folks cooked in one building, to keep the heat out of the house in the summer. You may have something like that. Also if this was a farm, where are/were the out buildings? Like a barn, corn crib, pig pen, out house,etc.
Lots of paperwork digging will save you a lot of time and sweat in your search. I followed a similar story a while back, lucky I guess for me, it involved a murder. Yeah I know, but digging through old newspaper archives, I found that the story folks told placed the location a long long way from where it actually was located. Also dependent on where you are, look for old archive aerial survey photos. For me PennPilots was a score. I found photos from the early 1900's of the area I was searching. And there were shots of all the buildings at that time, that are now long gone. Wouldn't even know they were ever there now.
And ditto using the Dowsers, long story/ short version. My farm has been in the family since the 1700's. Always heard stories of "something" that was left there. I posted some shots of the area, and had a couple of places picked out by more then one Dowser. Ain't saying anymore on that one.
A lot of the times a cache is left where it's out of the normal path, but close enough the owner can keep an eye on it.
Best of luck on your hunt.