Ralph:
Not sure I understand your example. If it was off-course, and then moved on-course, I think Klees has got them beat.
Please explain?
This might still come back to an earlier question I asked; Are you ONLY interested in shops that are still in operation, or if any shops existed pre-1910/1915?
It is very likely the oldest STILL IN OPERATION.
What date are they adopting as their start date, 1910 or 1915?
Smith Herd & Yeoman was only together for about one year and was an off course retailer in 1897-98.
Herd & Yeoman continued, as an off course retailer, after Smith left, 1898 until the teens or early 20s.
Herd left and W. Yeoman continued on as an off course shop.
THere were a number of off course shops in the east coast pre-1900. I don't know if any still exist.
The first one I listed is your best bet. AL Johnson, Boston -pre-1905.
Slazenger had a shop pre-1905, possibly pre-1900.
As for research check the want ads in old golf mags. Off course advertised quite a bit.