Anthony,

I agree that Johnson's regt [later Hawthorn's] was at Camp Nelson, but not Gipson's mounted Battalion, which was later Hawthorn's Inf Bn, and finally Chew's Inf Bn. I just don't believe this evolving battalion was ever at Camp Nelson.

Hawthorn was not assigned to command Johnson's regiment until November, long after the regiment had left Camp Nelson for NW Arkansas.

11/3/62 Camp on Mulberry, S O #30
Upon the recommendation of the Co officers of Johnson’s regt of Ark inf, the following persons are assigned to duty as the Field Officers of that Regt, subject to confirmation by the War Dept:
A. T. Hawthorne, to be Col, in the place of Col Johnson, resigned.
Maj. C. Polk to be LtCol in the place of LtCol Ringo, resigned.
Lt. J. B. Clarke to be Major in the place of Maj. C. Polk, promoted to LtCol
All to make rank from this date. The Regt will hereafter be known as “Hawthorne’s Regt of Ark inf.”
VI. Col A. T. Hawthorne is relieved of the command of “Hawthorne’s Bn,” Col. Brooks Brigade, and will report here for duty and [command of] his Regt.