Just to chime in... since I lived in TN for a while it would be interesting to do as some suggested to me: Let Memphis/Shelby County cede to Mississippi. I wonder if it would make TN the most heavily red/atlas-blue state and flip Mississippi.
We calculated that somewhere, and giving TN-09 to Mississippi (the TN-08 section of Shelby County is actually GOP-leaning), Romney would have won New Mississippi narrowly, probably pending a recount. ElectionsGuy calculated that the difference would have been a mere
790 votes!! He would have won New Tennessee by 30, which would have been good for his 5th largest win, behind Utah, Wyoming, Oklahoma, and Idaho. I would bet, though, that New Tennessee would be neck-and-neck with Oklahoma and West Virginia for Trump's biggest margin this year, while New Mississippi would be voting for Clinton.
https://uselectionatlas.org/FORUM/index.php?topic=218324.0