I have been researching my husbands family for the past few years. My initial source of information was my Mother in Law. I recommend that you ask your elderly relatives for what information they have about the Ancestors you are researching. This can be a wonderful source but sometimes it can lead you down the garden path. A phone call last night to my Mother in law reviled some information about an Aunt who she said had died as a teenager. In conversation she just happened to mention that the Aunt had married and she gave the surname of her husband. I was able to find the marriage record without any trouble.
For those of you who are stuck with the brick wall, just have a conversation with your elderly relative again, who knows what it may reveal.