Hi Jay,
Tina's brother Donald was the branch I tag on to. Not John Donald and not Donald John, it is Donald Cameron b. 1867 and married to Christina Cameron from Aharacle. Their son, Donald John Morrison Mackinnon Cameron, was my father. I'm in the JPG (the third son) of that branch.
I use an Apple Mac computer and bought MacFamilyTree genealogical software for my research (£49). It only works on Mac computers. It also comes with free website hosting in the purchase price. It is far superior (IMHO) to all other family tree applications on any platform. It also comes with many extras that you don't get with other apps. It is integrated directly with the LDS FamilySearch website giving free access to a worldwide database of genealogical info based in Salt Lake City, USA. It allows presentation of all, or part of, your tree in a huge variety of ways and formats.
Any info you feel you can pass me about the Johnston family, and or your own branch, would be gratefully received. I will be sending you a private message via rootschat with additional info.
Ken