I see this thread is indeed quite old, so I hope it still finds you. I faced a similar problem in linking a confirmed Balquhidder lineage with the family tradition of Craigdarroch origins. My directprogenitor named one of his farms 'Craigdarroch' in honour of his lineage. Interestingly, my family tradition also claims relation to the famous Anna Laurie (she was indeed quite the celebrity), however there has been no indication of direct decent from her, she was an in-law - which is perhaps something to consider.Many Ferguson families claimed relation to her (legitimately or not) in times gone by due to her notoriety.I personally believe my family to have a connection to the Fergussons of Craigdarroch a generation or two preceding the Alexander who was married to Anna Laurie.
I have compiled a substantial amount of circumstantial evidence to suggest a strong possibility of one or more Balquhidder families having originated from Craigdarroch. The book "Records of the Clan and Name Fergusson, Ferguson and Fergus" alludes to several such circumstantial links.Quite interesting considering the book was first published at the conclusion of the 19th century.
Please feel free to email me, or reply to this thread if you are interested in me sharing a quick summary of the evidence which I have compiled.