If you are speaking of the Inn at Rancho Santa Fe which is near Jamul, it would not be surprising if it were haunted. This inn, in continuous operation since the early part of the 20th century, has hosted Presidents, royalty and captains of industry as well as the entertainment elite. It is a well-known respite for those in high-stress jobs as well as those of us who just are looking for a wonderful place to unwind for a few days.
I knew the family that runs the Inn back in the late 1960's when I went to a private school in San Diego. He now owns the Inn as far as I know, and he never mentioned anything about hauntings or ghosts. But of course that might have been bad for business back then.
If you are speaking of another 'Rancho Inn' then I'm afraid I can't help you on that one.