Believe it or not, but you CAN locate treasure room sites by sitting in your home. All you need are topo maps, like the atlas style topo books (because these books contain the entire State), or an ability to scan satellite images of earth.
These treasure room "lands" or "properties" where the treasure rooms ar elocated are generally, but not always, in the shape of the OWL symbol. For a better understanding of what I am talking about, go to the following web site and map, and look at the property lines of this property:
search "1836 Map of Texas" that is found at the Stephen F. Austin State University.....then look for the property labeled "Granted to Stephen F. Austin, 1827". This property is in a profile shot of an OWL, and Stephen Austin, himself, laid out this land purposely in the shape of the OWL.....BECAUSE THERE IS/WAS A TREASURE ROOM(S) ON THIS LAND.
Now, when kicking back at home anhd sucking down a few cold ones, look on your topo for land in this same shape. It may be land, and PREFERABLY IS land, that exists between two water sources (these water sources will be used as death traps in the tunnel). Look at how many water sources there are on this property of Mr. Austin's.
Looking at topos atlases for these treasure rooms is the simplest way. Be aware that the "owl shaped properties" that you fiind may and can be the opposite profile shot as that of the Austin property in Texas. Also be aware that the OWL can be more abstract (not as clear to see) than the Austin owl, or it may be even more obvious that the Austin owl.
Folks, I KNOW this works. I know it's the easiest way to locate treasure room sites.
Once you find these properties, then go to them and look for the treasure signs and symbols that will help you to pin-point the place to dig. Look for the water sources that will have trees growing along them, and look for the bent-limb trees.