Good morning Doug.
Welcome to the Kessinger genealogy "hobby".It's sometimes fun; other times frustrating, but always interesting.
Thank you for your thoughtfulness and kind words about my wife Deloris.
She was a very unique and caring person; and she loved researching the family, and meeting "new" cousins.
If you haven't read it already, you might look at the posting my wife made (#895) entitled:GUIDE TO DETERMINING YOUR KESSINGER FAMILY LINE.
I'm fairly certain that your branch of the Andreas Kessinger family, is decended from his son Mathias Kessinger.
You probably have already found the following information on Hiram and Rowena.
The following Biographical sketch was copied from the book "HISTORY AND BIOGRAPHY COUNTIES OF WHITE AND PULASKI, INDIANA. Historical and Biographical. Illustrated. Chicago; F.A. Battey & Co., Publishers. 1883.
page 729, White Post Township, Pulaski County, Indiana.
"HIRAM KESSINGER was born in Washington County, Maryland, February 2, 1823, and is one of the nine children of JACOB and MARGARET (BEARD) KESSINGER, named as follows: JACOB, THEODORE, BENJAMIN, HIRAM, LUTHER, MARY (deceased), MARGARET, LUCINDA and GEORGE. The father was born in Maryland, took part in the war of 1812, and was engaged in a variety of occupations during life, such as tanner, merchant, manufacturer of earthenware, tinner and farmer. He was well educated, and was quite a linguist; he died in Harrison County, Indiana, in 1838. HIRAM KESSINGER came to Harrison County with his father in 1837, and he there was engaged in farming and merchandising. In January, 1870, he came to this township. He was married July 17, 1859, to ROWENA GAITHER, and has had born to him four children - THOMAS, CAROLINE, WALTER, and MARGARET, the last named deceased. In February, 1862, he enlisted in the Fifty-third Indiana Volunteer Infantry. Two months later, he became Ward Master in the hospital, and then Steward, holding the last-named position until mustered out in July, 1865. He was present at the sieges of Corinth, Vicksburg and Jackson; at the battle of Kenesaw Mountain, at the siege of Atlanta, at Jonesboro, with Sherman on his renowned march, at Savannah, Columbia, Raleigh, and other points. He owns a fine farm of 100 acres, two and a half miles south of Medarysville, raises a variety of crops, and has a neat residence and commodious outbuildings."
Hope this is of some help to you; if I can supply any additional information, will be happy to do so.
Best wishes, and good luck on your family search.