Hi, Matt . . .
I still get email notifications, even though I haven't been active on this board in years. I do have a copy of Balfour's book - I'll have to dig it out and see if it has the info you're looking for.
According my great-grandpa's Service Record, he was in a hospital in Williamsburg, VA (due to a gunshot wound) during most of the Overland Campaign. Haven't determined yet where he was when he was shot, or if this was something that flared up from an earlier gunshot wound, rather than a new wound.