|Ok, found the story and the book I was looking for. Christopher Coleman's Ghost and Haunts of the Civil War, chapter 10 The headless Phantom of Cedar Lane. The setting is Montgomery House, which is located on Cedar Lane, on the outskirts of Nashville. Ot's explained that Mrs. Montgomery was a staunch Confederate and while many of her neighbors fled the area followin the fall of Forts Henry and Donelson, she chose to stay put. Officers from the provost marshall's office arrived on her doorstep with orders to turn the house into a hospital for the Fedearl army and she was to leave as soon as possible. Mrs. Montgomery stripped the house of everything and buried the family silver and other valueables in the rose garden. Then she set fire to the house then set her slaves free before setting out for Natchez Trace. But this last action was her death as she ended up in between the lines in the middle of a skirmish and was decapitated by a cannonball.
The story then goes to local legend time saying her ghost returned to the burned out shell of her ancesteral home to guard the treasure buried there. Years after the war a group of young men finally dig up the treasure, or at least a part of it, which leads to Mrs. Montgomery to stop haunting the home. Maybe all she'd been waiting for was some of the local population to find her valuables, maybe she no longer had anything to guard and no reason to stay.
While looking for that one I came across another in Nancy Roberts' Ghosts of the Carolinas. It's not actually about buried Civil War treasure, but does deal with the war and buried treasure. Treasure Hunt tells the story of how a couple of junior officers of the62nd Ohio went looking for pirate treasure in the middle of the fighting around Charleston in July, 1863. According to the story General Gillmore order all blacks living on Folly Island to be removed to Port Royal before the fighting got started in earnest. Supervising this task was one Lt. Yokum of the 62nd Ohio. Yokum went to the cabin of an old woman who refused to leave and it was from her that he learned of the treasure. She claimed that her family had lived in the area, supposedly in that same cabin, dating back to the Golden Age of Piracy. According to the story Yokum believed her to be around a hundred years old (which would have still made her a bit young as the Golden Age ended around the 1730s at the latest and probably some time in the 1720s) and thus believed she was telling him a true story of how her family had watched a group of pirates bury
Six chests of gold, silver, and jewels
between a pair of nearby trees. Once the chests were in place the pirate captain proceeded to run through one of the men with his sword so he'd serve as an eternal guard for the treasure. The the Pirates buried treasure and body and left. No one ever dug up the treasure or even tried to dig it up.
That is not until 1863. Yokum managed to get the old woman to leave after she told her tale. The that night he and Lt. Hatcher, also of the 62nd, returned to the cabin and then to the two trees the woman had pointed out to dig up the treasure. But what they dug up instead was the ghost of the dead pirate, which chased off the two officers before they reached the treasure. This story was supposed to have first been published in 1908 in a book by Francis Moore, a friend of Yokum and a former Federal army officer himself. Supposedly neither Yokum nor Hatcher told anyone the story for fifty years. Then at a veterans' reunion Yokum told it to moore who published it in his book.
As I said, maybe these could be ideas for a sequel movie