Maybe this will help. I've been a programmer for 30 years now and do little that is not "logical". This includes treasure hunting and I might be called the Mr. Spock of Research.
When I move to a new area I get a few local hstory books and read those. To get an idea of what the place is like and where the old towns are.
Then I look around for the resources I might need. Where are the old newspapers, where are the historical archives, where are the historical socities, where are the libraries, state library, state archive, colleges and universities, private libraries or organization libraries. These are the places that will have original records.
Then I THINK!
What I want is something valueable and metal. This means coins of course but also other collectables. There are other things you can chase but with a metal detector you need metal.
The whole point of research is to find a precise, specific location to go dig. If the location is plus or minus 5 miles you might as well not go.
I try to find a really good lead before I go out.
Once you get into the archives you will find amny MANY leads for caches. I supplement these with articles form newspapers of the day which contained truthful stories of the events as they occurred. Sort of like eye witness accounts from 200 years ago.
I used to research original records from the US mint in Phil. for lost shipments of coins from 1850 and before. These records are stored in the national archives at several points in the US. I found several shipments lost.
I also found an insurance company where I could look thru their records from before 1850. What is an insurance company? They are a business that pays you if you lose something valueable. Right! I want to find reports of valueable things which were lost and here is a company/archive just full of lost valueable things. Geez. It doesn't get any easier. And they keep good reocrds. Who, what, date, value, and the story details.
Like c.w. relics. How about visiting the factory that made Texas butons and checking out back to see if they had a trash pit? Likely they made square plates too.
I should point out, anything made of metal and collectable and old will work. Just find out where they were made, shipped, or lost and go dig there. You need an archive for some of this but any good library has some of it. Even old bottles, you know.
I looked for old crimes in my area, Virginia. 1800 and before. I looked for crimes where coins were stolen and not recovered. You understand? In county court house records.
If you can get access to insurance company records from before say 1800 this would be the best you could do.
You can find caches others don't even know exist. What was once worth $100 can now be worth $100,000