The theme of this post is that coordination is a superior principle to simultaneity and thus the idea that the coordinated offensive serves a Jominian purpose better than simultaneous offensives.
The temptation is to go off on a tangent on Scott's operational art, demonstrated in these first and second offensives, but I am not going to do that here. Will let the first offensive timeline speak for itself and hope its message is audible to the late war reader.
Scott's management is highlighted in bold. The effects of Scott's management are show in italics. Comments are [in brackets]. The rest is interesting noise and context.
May 23. Virginia votes for secession. (The CW Day by Day, Long)
May 24. Scott asks McClellan, in Ohio, if he can move against Grafton. (OR)
May 24. Butler reports his arrival at Ft. Monroe. (OR)
May 24. Scott orders Patterson to push into Hagerstown, Frederick, and Cumberland. He then modifies the order making Cumberland's taking optional. (OR)
May 26. McClellan sends three column into Virginia. (Long)
May 27. The Dept. of NE Va. is created under McDowell. (OR)
May 27. McDowell seizes Alexandria. (OR)
May 27. Butler seizes Newport News in an amphibious attack.
May 30. McClellan's column under Kelley takes Grafton. (Long)
June 1. Scott orders Patterson to advance on Harpers Ferry. He says, "I will make a demonstration beyond Alexandria." There is no deadline.
McDowell's cavalry probes Fairfax County. (Long)
June 3. McClellan's victory triggers the "Phillippi races" in Virginia. (Long)
June 3. AG Townsend asks McDowell to estimate the composition of a column "to be pushed toward Manassas" "say in four or five days to favor Patterson's attack on Harpers Ferry." (OR) [Note the flexibility!]
June 4. The Union navy shells Pig Point on the James River.(Long)
June 4. McDowell answers Townsend proposing 12,000 infantry, two batteries and 6-8 "companies" [sic] of cavalry advance on Manassas. (OR)
June 6. McClellan asks Scott for permission to muster in Virginia regiments. (OR)
June 6. Butler proposes to attack toward Norfolk. (OR)
June 7. The Union navy blockades Apalachicola, Fl. (Long)
June 8. Tennessee votes for secession. (Long)
June 8. Scott orders Patterson to Harpers Ferry without specifying a date. Scott orders Stone to Edward's Ferry opposite Leesburg as a "diversion" that "may be turned into an effective cooperation, without specifying a date. (OR)
June 9. Butler undertakes a night march against Big Bethel. (Long)
June 10. AG Townsend, on Scott's behalf, directs Butler to attack Suffolk - without specifying a date. Butler attacks Big Bethel in daylight. (OR)
June 10. Stone fights his first battle en route to Edwards Ferry (Long).
June 13. Townsend advises Scott that Stone is on the march and that on the 17th or 18th, McDowell will start his advance against Manassas. (OR)
June 13. Lew Wallace drives Rebels out of Romney, Va., with a regiment of Zouaves detached from McClellan's command and attached to Patterson. He then continues his march to Cumberland, his objective. (OR)
June 13. Johnston communicates his lack of confidence in holding HF for the CSA. (Long)
June 14. Fitz John Porter, Patterson's senior staff officer, coordinates Stone's movements with Patterson's. (OR)
June 14. AP Hill captures Romney as Wallace leaves to complete his march from Western Va. to Cumberland, Md. (Wiki)
June 14. Stone fights another battle at Seneca Mills, Md., en route to Edwards Ferry. (Long)
June 15. Patterson's forces advance on Williamsport and Martinsburg. Patterson says he cannot cross the river to take HF until the 19th. (OR)
June 15. Johnston evacuates HF. He says he fears a union of Patterson and McClellan. (Long)
June 15. Stone fights another battle at Conrad's Ferry en route to Edwards Ferry. He takes Edwards Ferry. (Long)
June 16. McClellan tells Scott he hears Patterson is "checked" at the Potomac in front of HF and offers to advance from western Virginia to join Patterson. Scott tells him there is "no need." (OR) [We will explore this interaction in a future thread on the concept of theatres of war.]
June 16. Patterson (actually his combatant commander, Cadwalader) takes HF, which has been evacuated. (OR)
June 16. Patterson reports to Scott that McClellan has sent a regiment to aid Wallace at Cumberland. (OR)
June 17. Stone fights yet another action at Conrad's Ferry.
June 19. Pierpont named governor of (loyal) Virginia. (Long)