Wesley Bradshaw didn't exist, either. That was a pseudonym used by Charles W. (for Wesley) Alexander, the publisher of "Washington's Vision". John Adcock at Yesterday's Papers says that Alexander, using his "Wesley Bradshaw" identity, had already contributed to a series of illustrated pamphlets that
purported to be true stories of murderers and female fiends, full of torture, murder and melerdrama, usually beginning on page 19, so a 64 page work was not all it was advertised to be.
(Note that Washington's Vision gets rolling on page 11.) Thus, if we believe the story Alexander tells in "Washington's Vision," he heard of an angelic prophecy crucial to the nation, and chose to publish it under the same pseudonym he used for exploitative potboilers.
In fact, a big part of Alexander's work was responding to recent public events with patriotic thrillers and legends. During and after the Civil War he wrote and published several novels such as Pauline of the Potomac; Or, General McClellan's Spy; its sequel Maud of the Mississippi, General Grant's Daring Spy; and the immortal The Angel of the Battlefield: A Tale of the Rebellion. In 1876, just in time for the Centennial celebration, Alexander came out with The History and Legends of the Old Liberty Bell in Independence Hall in Philadelphia. "Washington's Vision" is part of that fictional output, not a historic link to Valley Forge.