Monocacy was fought on July 9, 3 days following his release from the hospital in Richmond. The distance between these points is about 150 miles. I would rather doubt that a Private could obtain the necessary transportation and also obtain the intelligence as to the location of his regiment. Just when he rejoined his unit cannot be ascertained from the available records.
My ggrandfather and two brothers, of the 43rd Tennessee, were there and may have seen President Lincoln watching from Fort Stevens. As it has been said, Lou Wallace having delated Jubal Early for a day in reaching the capital,
"Early was Late"