Denise,
This is not all that you are looking for but I hope it helps you. As Jim said in his post, perhaps there might be more in his military service record but there are no guarantees. I can only tell you that in my case, I hit the jackpot in terms of records of my Great Grandfather.
Here is what I could find on your ancestor;
John W. Evans was a private in company A of the 101st Infantry regiment. He was from Indian Creek, Cass CO Illinois. He was 28 years old and was 5'71/2" tall. Had dark hair and gray eyes. Complexion was dark. He was married at the time of enlistment and was a farmer. He was born in Rushville, Illinois in Schuyler County. He enlisted at Meredosia Illinois on Aug. 10, 1862 by Chas. Gove for a period of three years service and was mustered in at Jacksonville Illinois on Sep.2,1862. He died on June 27,1864 at Jeffersonville Indiana for war wounds.
I hope this helps you. I know that there is a Indian Creek in Cass county but I don't know if there ever was a village by that name so it might just be a geographical location that is given. Hope this helps you.
Frank Campo