In my opinion, the successful Union advance in Kentucky and Tennessee between January-March 1862 definitely shaped the course of following actions later fought in the West.
With some support from the Trans-Mississippi District, Sidney Johnston can delay the evacuation of Bowling Green which brings him enough time to fortify Nashville. Therefore, Van Dorn's forces is reduced to the Missouri division under the command of Sterling Price (8,000), one Texas cavalry brigade under James McIntosh (3,000) and one Indian brigade under Albert Pike (2,500), all in all 13,500 men to confront an equally-sized Union force. Ben McCulloch's Arkansas units (4,000) are transferred to either Polk or Buckner. Floyd and Pillow can be transferred to New Orleans or to Pensacola.
Lovell keeps at least 4,000 infantry manning New Orleans Defenses to prevent the further capture of the town. Bragg stills transfer part of his command (8,000) to Sidney Johnston, sooner than historically. Crittenden prevents Zollicoffer to attack Thomas at Mill Springs and await for Union advance, securing Cumberland Gap with his three brigades (Zollicoffer's, Carroll's and Rains').
Order of Battle January 10, 1862
Western Department : Gen. Albert S. Johnston (46,000 to 54,000 men)
- - - Cavalry Brigade : Lt-Col. Nathan B. Forrest
- - McCulloch's Division : Brig-Gen. Benjamin McCulloch (4,000)
- - - Hébert's Brigade : Col. Louis Hébert
- - - McNair's Brigade : Col. Evander McNair
- Army of Central Kentucky : Maj-Gen. William J. Hardee (24,000)
- - Hindman's (Hardee's old) Division : Brig-Gen. Thomas C. Hindman (6,000)
- - - Marmaduke's (Hindman's old) Brigade : Col. John S. Marmaduke
- - - Wood's Brigade : Col. Sterling A. M. Wood
- - - Cleburne's Brigade : Col. Patrick R. Cleburne
- - Buckner's Division : Brig-Gen. Simon B. Buckner (6,000)
- - - McCausland's (Floyd's old) Brigade : Col. John McCausland
- - - Baldwin's Brigade : Col. William E. Baldwin
- - - Brown's Brigade : Col. John C. Brown
- - Breckinridge's Division : Brig-Gen. John C. Breckinridge (6,000)
- - - Trabue's (Breckinridge's old) Brigade : Col. Robert P. Trabue
- - - Bowen's Brigade : Col. John S. Bowen
- - - Clark's Brigade : Col. Marcellus J. Clarke
- - Tilghman's Division : Brig-Gen. Lloyd Tilghman (6,000)
- - - Heiman's Brigade : Col. Adolphus Heiman
- - - Drake's Brigade : Col. Joseph Drake
- - - Johnson's Brigade : Col. Bushrod R. Johnson
- District of Columbus : Maj-Gen. Leonidas Polk (12,000)
- - Cheatham's Division : Brig-Gen. Benjamin F. Cheatham (4,000)
- - - Smith's Brigade : Col. Preston Smith
- - - Stephens' Brigade : Col. William H. Stephens
- - Clark's Division : Brig-Gen. Charles Clark (4,000)
- - - Stewart's Brigade : Brig-Gen. Alexander P. Stewart
- - - Russell's Brigade : Col. Robert M. Russell
- - McCown's Division : Brig-Gen. John P. McCown (4,000)
- - - Walker's Brigade : Col. Lucius M. Walker
- - - Gantt's Brigade : Col. Edward W. Gantt
- District of East Tennessee : Maj-Gen. George B. Crittenden (6,000)
- - - Zollicoffer's Brigade : Brig-Gen. Kelix K. Zollicoffer
- - - Carroll's Brigade : Brig-Gen. William H. Carroll
- - - Rains' Brigade : Col. James E. Rains
- Bragg's Command (Dept. Alabama & West Florida) : Maj-Gen. Braxton Bragg (8,000)
- - Withers' Division : Brig-Gen. Jones M. Withers (4,000)
- - - Walker's Brigade : Brig-Gen. Leroy P. Walker
- - - Chalmers' Brigade : Brig-Gen. James R. Chalmers
- - Gladden's Division : Brig-Gen. Adley H. Gladden (4,000)
- - - Jackson's Brigade : Brig-Gen. John K. Jackson
- - - Anderson's Brigade : Brig-Gen. James P. Anderson
- Lovell's Command (Dept. Southern Mississippi & Est Louisiana) : Maj-Gen. Mansfield Lovell (4,000)
- - Ruggles' Division : Brig-Gen. Daniel Ruggles (4,000)
- - - Gibson's Brigade : Col. Randall L. Gibson
- - - Pond's Brigade : Col. Preston Pond
Now, the Confederates have the choice of fighting Grant at Fort Donelson, waiting the Union attack at Nashville or launching their own offensive against either Grant or Buell.