I think this can explain on the best of days, the length of time it took to get news:
From Manassas to Appottamox (Longstreet)
Chapter II.—From New Mexico To Manassas.
The War-Cloud—The Journey Northward—Appointed Brigadier-Gen-eral-Report to General Beauregard—Assigned to Command at the Scene of the First Conflict—Personnel of the Confronting Forces—Description of the Field of Manassas, or Bull Run—Beauregard and McDowell of the same West Point Class—Battle of Blackburn's Ford—Early's Mistake—Under Fire of Friend and Foe.
I was stationed at Albuquerque, New Mexico, as paymaster in the United States army when the war-cloud appeared in the East. Officers of the Northern and Southern States were anxious to see the portending storm pass by or disperse, and on many occasions we, too, were assured, by those who claimed to look into the future, that the statesman would yet show himself equal to the occasion, and restore confidence among the people. Our mails were due semi-monthly, but during winter seasons we were glad to have them once a month, and occasionally had to be content with once in six weeks. When mail-day came the officers usually assembled on the fiat roof of the quartermaster's office to look for the dust that in that arid climate announced the coming mail-wagon when five or ten miles away; but affairs continued to grow gloomy, and eventually came information of the attack upon and capture of Fort Sumter by the Confederate forces, which put down speculation and drew the long-dreaded line.
number of officers of the post called to persuade me to remain in the Union service. Captain Gibbs, of the Mounted Rifles, was the principal talker, and after a long but pleasant discussion, I asked him what course he would pursue if his State should pass ordinances of secession and call him to its defence. He confessed that he would obey the call.
It was a sad day when we took leave of lifetime comrades and gave up a service of twenty years. Neither Union officers nor their families made efforts to conceal feelings of deepest regret. When we drove out from the post, a number of officers rode with us, which only made the last farewell more trying.
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Reading of Longstreet's travel, he was already on the move before getting news that his resignation from the U.S. Army's officer's commission took effect as of June 1st, 1861 and didn't reach Richmond's War Department until June 29th, 1861. (And Longstreet took the swiftest route to get there).
Other then the telegraph -- news and mail would most likely be on stage-coaches or mail express on horses, e.g. Pony Express.
Passing through Indian territory and gangs of thieves, it is amazing that it took that short of time. Especially today with our rush hours around Washington, DC.
Just some thoughts.
Respectfully submitted for consideration,
M. E. Wolf