I am amazed that the Old Testament covers the lives of Adam through Jacob in about 5% of its pages and yet the time span is about 65% of the time covered. Moses knew about the lives of these early fathers however did not write much about it or these writings have been lost. The sad part is that even with the small amount of writings about these men we have clear declarations that Adam, Enoch, Noah, Abraham, Isaac and Jacob all saw the face of God, conversed with him and could say they knew him.
Jesus declared, to obtain eternal life one must know God and the Messiah. You cannot truly know the Messiah unless you know God. I would think that it would be more important to know how these men lived their lives, how they worshiped, what they did to come to know God than all the stories about the disobedience of the children of Israel and how they rejected and killed the prophets that God continually sent to them. Obviously a lot more happened than was written in the bible. This is where we need to have the Holy Spirit for our guide to be taught, what did these fathers do!
Abraham was born in one of the cities of Nimrod, Ur and his fathers were deep into idol worshiping. So it stands to reason that he did not learn about God from his fathers. What the bible chronology tells us is that Abraham was about 60 when Noah died and the Shem died after Abraham died. Therefore it is reasonable to believe that before God called Abraham to leave Haran when he was 75 he would have been instructed by Noah and Shem about the way to worship God and have faith in the coming Messiah. I believe this to be so and there are non biblical writings that talk about this. This is one of the reasons I believe Melchizedek is Shem who received a new name from God just as Abram and Jacob did. If Abraham had been instructed by Shem for many years then it would have been a wonderful reunion when Melchizedek came to meet Abraham on his way back from getting Lot. It is obvious they knew each other well.
Regardless of the details, Abraham worshiped in the same manner that Noah, Enoch, Abel and Adam did. Abraham also came into the presence of God many times. These men taught from experience, not by interpreting the writings of others who lived thousands of years before them. They did not argue over the nature of God because they walked and talked with Him.
Being born into the right family did not guarantee an audience with God; each man must follow the same pattern to know God. The pattern that I see is that they had no other gods before the Father, they learned to hear him and do what he asked them to do. They taught their families, understanding that their families needed to choose for themselves. They invited others to worship God and come to know him.