I think I have now resolved the matter. Long story short, I now believe that the most likely route that Jones took was the one described by Blake, along the east-west trail that crosses Little Rocky Run about 1400 yards from Blackburn's Ford NOT the crossing closer to Centreville using the Braddock Road.
Based upon the above and what follows I think that the scale in the Gottfried map should be 'feet' not 'yards'.
My main reason for now concurring with Blake's assessment is the report of Davies (
https://babel.hathitrust.org/cgi/pt?id=coo.31924077730186&seq=444&q1=) which says (my emphasis in bold and additions in brackets):
"The Second Brigade, under my command, was in readiness to march from camp at 2.30 a. m., but the road was so blocked with moving troops that my brigade shortly after daylight took a parallel route through the fields, Greene’s battery in advance, till it struck the road leading to Blackburn’s Ford,
about one mile south of Centreville. At this point Colonel Miles gave me directions to assume the command of Richardson’s brigade [this may be why Richardson later saw fit to claim Miles was drunk], and to take position in front of the batteries at Blackburn’s Ford on and near the battle ground of the 18th instant, and make the demonstration of attack, in pursuance of General McDowell’s orders. I immediately ordered forward the two 20-pounder rifled guns of Hunt’s battery [Richardson's brigade], commanded by Lieutenant Edwards, into an open field,
about eighty yards east of the road from Centreville to Bull Bun and on a line with the place where our batteries were playing on the 18th instant,
and about fifteen hundred yards from the enemy’s batteries at Blackburn’s Ford, and commenced a rapid firing. I ordered the Eighteenth Regiment forward as a protection to this battery, in the open field, and formed line of battle facing the enemy, the Thirty-second Regiment being held in reserve on the road just in rear.
Having ascertained from my guide that there was a road without obstruction leading from the Centreville road to the east, and then bearing off toward the south in the direction of the enemy’s position, and which could be seen about half a mile distant to the east from Lieutenant Edwards’ battery [Richardson's brigade], I ordered the Sixteenth and Thirty-first Regiments New York Volunteers on to this road at its junction with the Centreville road; one regiment deployed along the road a considerable distance, and the other remaining in column to protect two guns of Hunt’s battery which I ordered to be stationed at that point. I then gave orders to Colonel Richardson to make such arrangements with regard to the defense of the position in front of the enemy’s batteries at Blackburn’s Ford (the immediate battle-ground of the 18th instant) as in his judgment the emergency of the moment might require. At this juncture, being about 10 o’clock a. m., and finding the ammunition for the 20-pounder rifle guns was fast running out, and having accomplished, in my judgment, from the movement of the troops opposite, which we could plainly see, the demonstration ordered, I ordered Lieutenant Edwards to cease firing.
About 11 o’clock Colonel Miles came on the ground, informing me that he had ordered forward the Sixteenth and Thirty-first Regiments from the positions in which I had previously placed them, and also the two guns commanded by Lieutenant Platt, and had also ordered forward the other two guns of Hunt’s battery into the open field where Lieutenant Edwards’ guns had been firing, and ordered the Eighteenth Regiment back out of the open field into the woods on the Centreville road as a reserve. The Thirty-second Regiment, by Colonel Miles’ order, remained as a reserve in column on the Centreville road, about three-quarters of a mile in rear. Colonel Miles then ordered me to continue the firing without regard to ammunition, which I did till I received an order to stop, about two hours later. As soon as Colonel Miles left me again in command I sent back the brigade corps of pioneers to the back road, whence the two regiments had been removed, with instructions to fell trees and completely block the road, which they effectually did. We had during the afternoon unmistakable evidence that a large column of cavalry and infantry had attempted to take us in rear by means of this road, for when they were returning, having been stopped by the fallen trees, Major Hunt, with his howitzers, and Lieutenant Greene and Lieutenant Edwards, with their rifled guns, poured a heavy fire into their column, the effect of which we could not ascertain, but it must have been destructive, as the distance was only from a half to three-quarters of a mile.
In the course of the day two companies, and later four companies, of the Thirty-first and two of the Sixteenth were, by Colonel Miles’ order, thrown forward to feel the enemy’s strength to the front and left in the direction of Bull Run. They found the enemy posted in the woods, and were recalled. They reported having killed several of the rebel scouts.
The afternoon, till about 4 o’clock, was passed in great inactivity, except the firing by the rifled cannon at moving columns of the enemy at great distances." [Some more action followed later, see report for details.]
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I also discovered that the cavalry action against Blenker on the Warrenton Turnpike east of Centreville did not occur until just after 2100. Blenker's report immediately precedes that of Davies in the official records. Here's an excerpt:
"The retreat of great numbers of flying soldiers continued till 9 o’clock in the evening, the great majority in wild confusion, but few in collected bodies. Soon afterwards several squadrons of the enemy’s cavalry advanced along the road and appeared before the outposts. They were challenged by “Who comes there?” and remaining without any answer, I being just present at the outposts, called, “Union forever.” Whereupon the officer of the enemy’s cavalry commanded, En avant; en avant. Knock him down.” Now the skirmishers fired, when the enemy turned around, leaving several killed and wounded on the spot. About nine prisoners, who were already in their hands, were liberated by this action. Afterwards we were several times molested from various sides by the enemy’s cavalry."
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So, what to do about Miles' division being fixed in the game? I tend to think it should probably stay fixed as Miles says he was ordered "on no account to get into a general engagement". Miles was placed near Centreville to act as a reserve and to protect Centreville (hence the building of defensive works there). It would be nice if he was permitted some freedom of movement beyond his original positions, but the game doesn't really permit such a thing. If 'released' he would be free to wander off to wherever the controlling player desires. So, I feel the designers did the only thing they could given the historical situation and the restrictions of the game engine, they had Miles division fixed unless released by Confederate action.