Mike --

I hope you don't mind a little post-Christmas nit-picking. You mentioned that your ancestor was captured in north Alabama on the way to the Army of Northern Virginia. Since General Lee was not appointed to command until the evening of May 31, 1862, and didn't rename the army until afterwards, it's more accurate to say that your ancestor was in captured while in transit to his regiment in Virginia.

On April 11, 1862, many Confederates were captured aboard a train passing through Huntsville Ala. Might your ancestor have been among them? If so, many prisoners wrote their names on the railway depot walls. I cannot imagine how he could have been captured earlier than April 11th unless the location is wrong.