GirlWithWolf: If you're in OK, I would highly recommend Oklahoma Treasures Lost and Found by "Jesse Rascoe" [Ed Bartholomew] (1971). It's long out-of-print, so you'll probably have to locate a copy in a public library or local historical society. You'll learn more from the "found" stories than from the "lost" yarns. Stories of successful treasure finds - both accidental and intentional - are blueprints for the perceptive person - they tell you what to look for, and where to look.
For example, I'm sure there are many moonshiner and bootlegger plants in Oklahoma. No knock on the citizens - your state is hardly alone in that. Then there are caches from professionals who delt in cash - doctors and attorneys, for example. Many farmers didn't trust banks, particularly after so many folks were wiped out in the Great Depression. Successful gamblers often hid part of their winnings.
I don't place a whole lot of faith in outlaw treasure tales. Although Oklahoma certainly had its share of men and women operating on the other side of the law. As I recall, the great lawman Bill Tilghman met his fate there, after a lifetime career of chasing badmen. Ramon F. Adams' Six Guns and Saddle Leather (1998) will guide you to reliable sources, if the topic is of interest. Like treasure hunting literature in general, much that is readily available isn't factual or otherwise reliable.
Good luck to all,
The Old Bookaroo