Where were the religious shrines of pilgrimage located?
If we were to assume that the Pentateuch is a consistent whole, and that it was written by a single, undisputed authority (Moses) then we would not expect to find contradictions within the manuscripts, and we would also expect to find later manuscripts deferring to ‘the facts' as outlined in ‘the divine word.' Later accounts disagree with Genesis, which shows that the authors either did not think that it was Moses who wrote the Bible, or that they did not consider Moses to be an authority they had to obey. This proves not to be the case. This demonstrates that in earlier times these manuscripts were not considered to have the unquestionable authority that was later imputed to them. Various authors working in various traditions felt free to nullify and contradict the authors of other manuscripts, including Moses, which shows that at the time of their composition, these authors probably did not consider it important to believe that it was Moses who wrote the Bible.
Where were the Patriarchs buried and from whom was this burial spot purchased? It depends on who you ask. If one wishes to be a a pilgrim on a pilgrimage to the tomb of the Patriarchs it would be important to nail down the facts, would it not? According to the Pentateuch,
"Then Jacob charged them, and said to them, "I am to be gathered to my people; bury me with my fathers in the cave that is in the field of Ephron the Hittite, in the cave that is in the field at Machpelah, to the east of Mamre, in the land of Canaan, which Abraham bought with the field from Ephron the Hittite to possess as a burying place. There they buried Abraham and Sarah his wife; there they buried Isaac and Rebekah his wife; and there I buried Leah-- the field and the cave that is in it were purchased from the Hittites." When Jacob finished charging his sons, he drew up his feet into the bed, and breathed his last, and was gathered to his people." (Genesis Chapter 49 verse 29)
"His sons carried him to the land of Canaan, and buried him in the cave of the field at Machpelah, to the east of Mamre, which Abraham bought with the field from Ephron the Hittite, to possess as a burying place. After he had buried his father, Joseph returned to Egypt with his brothers and all who had gone up with him to bury his father." (Genesis Chapter 50 verse 13)
So then the Tomb of the Patriarchs was in Machpelah and it was Abraham who bought it from Ephron the Hittite. This version of events is contradicted in the book of Joshua. This indicates that at the time of these writings no one knew where the tomb of the Patriarchs was located, and, much as it is today, there are variant traditions concerning where such and such an event took place, and where the ‘official' spot of pilgrimmage is located. At the time of the composition of the variant traditions no one considered the alternative version to be indisputable, as is demonstrated in their feeling free to expound their own version of events. In Joshua we read that the tomb of the Patriarchs was located in Shechem, and that Jacob bought the burial ground from the sons of Hamor, presumably before his sons slaughtered the entire town for the rape of their sister Dinah (a variant version of the relationship between the Patriarchs and Hamor).
"The bones of Joseph which the people of Israel brought up from Egypt were buried at Shechem, in the portion of ground which Jacob bought from the sons of Hamor the father of Shechem for a hundred pieces of money; it became an inheritance of the descendants of Joseph." (Joshua Chapter 24 verse 32)
There is still another variant of the story found in the book of Acts. The Tomb of the Patriarchs is said to be in Shechem, in agreement with Joshua, but it was Abraham who purchased the tomb from Hamor, in agreement with Genesis. This could be considered ‘the middle of the road' approach to resolving disagreements among traditions, but in its own way it introduces more problems than it solves. According to Genesis, the encounter with Hamor took place long after the death of Abraham, during the days of his great grandsons.
"And Jacob went down into Egypt. And he died, himself and our fathers, and they were carried back to Shechem and laid in the tomb that Abraham had bought for a sum of silver from the sons of Hamor in Shechem." (Acts Chapter 7 verse 15)
"Abraham breathed his last and died in a good old age, an old man and full of years, and was gathered to his people ... the field which Abraham purchased from the Hittites. There Abraham was buried, with Sarah his wife. After the death of Abraham God blessed Isaac his son. And Isaac dwelt at Beerlahairoi." (Genesis Chapter 25 verse 8)
" ... and buried him in the cave of the field at Machpelah, to the east of Mamre, which Abraham bought with the field from Ephron the Hittite, to possess as a burying place." (Genesis Chapter 50 verse 13)
These differences indicate that the various books of the Pentateuch were not considered ‘authoritative' during earlier times, in that variant traditions existed and the authority of Genesis, for example, was not recognized as final. The evidence also suggests that the author of Acts took half from this tradition and half from that tradition, to weave together a less than satisfactory 'compromise', a compromise that no doubt would have pleased neither side of a divided camp. It does show that the writer recognized that the traditions were contradictory (how could he not notice) which is more than many in the pulpit are willing to confess, and in this case at least, he didn't put much work into 'harmonizing' inconsistent passages, a terribly bad habit picked up by later generations of theologians who labored intensively (to no purpose).