I believe Glenconglass farm is the farm at NJ174223.
It is still very much in use.
There is a stream flowing SW coming down to Glenconglass farm - visible on the modern 1:50000 map. I have a copy of an ancient OS map that calls the stream the "Allt na h-Ellick"
A few hundred yards up the stream is an old ruin - little more than a gable end. I guess this is the Aultnahillick farm mentioned in the 1841 census with John Smith and his family.
This link is (I hope) centred on the Altnhillick ruin.
http://maps.google.co.uk/?ie=UTF8&ll=57.286303,-3.36849&spn=0.002882,0.008208&t=h&z=17There is a picture of the modern Glenconlass farm at.
http://www.geograph.org.uk/photo/51088. The farm house and older buildings are behind the big modern barn.
There are very brief references to these Smiths as tenants of farms in the book Lordship of Strathavon by Victor Gaffney. The Gordon estate papers and rent accounts for at least some of these farms still exist in Edinburgh.
I understand they suggest farming on the Ellick hillside was not easy. In a poor year the rent had to be held over to the following year.
Stories told to my Grandfather around 1900 claimed the family was related to John Smith, the first licensed whisky distiller. They include tales of how John escaped ambush in an inn by shooting into the fire, filling the room in soot and smoke, and escaping in the ensuing mayhem. The same story appeared more recently in Glenlivet advertisements. But we have yet to find any supporting historical record - and so far the dates don't fit very well.
I haven't looked for Grace Cameron and Kincairn.
Happy New Year!