Inver has a really active Historical Society. One lady called Helen Meehan has written a book on the history of Inver Parish. - http://freepages.genealogy.rootsweb.ancestry.com/~hiflyte/Book_List/Meehan.html
Her book is fantastic.
You should also check out Donegal Genealogy resources - http://freepages.genealogy.rootsweb.ancestry.com/~donegal/
I hope this this helps you in some way.