Please forgive my ignorance of the proper protocol but I would not spend one minute looking for John Murrell's treasure unless we are talking about the guy who makes the really good bacon and smoked sausages. Magnsdad, the area you are in is very ripe with treasure. I would, if i were you, concentrate on the West-Kimbrell gang's many, many treasures in and around Montgomery, La.
West and Kimbrell both road with the James under Quantrill during the Civil War. After the war they established the largest criminal network known, at that time. It stretched from Natchez Miss. to Nacogdoches, Tex.
There are three lost mines (silver and lead) in your area. There were four but one was found about 30 years ago. (It was a gold producing mine and to the best of my knowledge still produces twenty or more oz. a year.)
Most people know the area between the Sabine and Los Adaes Mission as the Neutral Strip not zone. The Adams-Onis Treaty did not satify the issue only the border. (See Athanase de Mezieres' work on the Border of Louisiana and Texas. It is filled with treasure leads.) My family settled in that area in 1799 and it was the area that I research for my Master's in History at USL along with Barney Rubble and Fred Flinstone. Yes, Betty Rubble was a cheerleader at USL at that time.)
There are too many treasures and books related to the life in the Neutral Strip to recall them all. All my research was lost in a hurricane in 1988 while I was living in Cankton, La.
About the treasure of the N.O. Mint, it may be real and it may not, but the West-Kimbrell gang did hijack the Union army payroll not far from your location. This is a very informative booklet written by a former newspaper editor from Montgomery and can be found in most libraries of the area. Look under subject heading of West-Kimbrell. A copy or two exist at Northwestern and ULL (former USL in Lafayette.)
I've hunted treasure in La. since 1966 and all I can say is that it is there. Do your research, double check your sources and if you find the big one bury some metal trash, i.e. cans plus a modern nickel or dime, to let the next man or woman know that you beat them to it. Beau champs. Cyrus.