Under feed bins or troughs. Water source spots. Corn crib floor. (chickens already mentioned). Barn corners and house corners ,inside and out. Under steps or thresholds. Pipes,beams,hollow walls.
Under outhouse seat off to one side or any corner, in or out.(When house is much wider than the hole it allows a false wall on one or both sides,or just dirt.) Dirt floored workshop was where a friends gramp kept a shotgun hid, as well as under house floor between joists. Smoke house or refrigerator used for a smoker or worm bed( outside underneath) Stumps, trees, or monuments. Fence stones,steppin stones,wood piles. Partially buried bath tub, ect.
Where ever a cache may have been the ol man seen it regularly enough to keep an eye on it probably, if he could get to it without being noticed.. Could have been once daily, maybe less, or in a spot he spent a lot of time around.
Before being able to throw a switch to illuminate a yard it did not matter if you could see it from the house so much. Some guys did not want their kids or spouses to see them home banking.
A good safe cache works when you are not home.
Wood heat and cooking meant another unheated building away from house even without a big barn sometimes to allow staying if a fire occurred. Lots of other uses for outbuildings anyway. A cache out of the house, while less guarded avoided a fire threat. But then buried silver in a dirt floor don't burn much...
Knowing more about the cache creator might help.
If he had a sip now and then discreetly where would he do it? Or if he hid some card playin money where might it have been?
Where I have cached may or may not relate to where he did. Today avoiding a detector is a natural requirement.
A junk car or lawn tractor with something in it/under it, hard to sort out (no I don't) Or under certain things.Or deep.
Gramps just wanted it dry maybe, and secured out of sight in a discreetly recoverable spot, or more.