Following your thinking but taking the known information you find John Thomas Gill as a Coachman with wife Elizabeth Wilson Gill at The Potteries Knottingley in 1881. He was born in Pontefract and children were born in Linslade and Leicester suggesting he returned to his roots so it looks as though the picture is of a hall in Yorkshire possibly/probably in the Pontefract Area where the family were employed. I presume the family emigrated so if you can find a shipping manifest it may give an address in England that gives a clue. A post on the Yorkshire Board might yield a result. The photo looks to be of a substantial Georgian House that may or may not still exist but the Georgian Society may be able to identify the architectural style and hence the house.