When Did the Exodus Occur?

Several years ago, Reader's Digest had an article about the biblical record of the nation of Israel. The author concluded that it was impossible to identify the time of the Exodus because there were no Egyptian records of them having entered or left Egypt. The article called attention to a problem I had run into earlier, and prompted me to study the matter further.
Most historians have accepted Ussher's Chronology as to the dates of events referred to in the Bible. Unfortunately, Bishop Ussher was not a very good mathematician. He allotted a period of about 230 years to the Judges. Adding up the time periods named for each of the Judges, we find that the period was at least 390 years, a discrepancy of 160 years. In addition, since the Bible never specifies how long Joshua and Samuel led Israel, he assigns each a period of about 20 years. Eli's administration is ignored completely.
Joshua is described as a young man in both Exodus 33:11 and in Numbers 11:28. It is reasonable to suppose that he was no older than Caleb, who was 80 at the end of the time in the wilderness. He died at the age of 110, making him leader for at least 30 years, and Joshua 24:31 tells us that Israel served the Lord all his days and all the days of the elders that out lived him. It is not unreasonable to suppose that his total impact extended to at least 40 years.
After the death of that entire generation, we find Israel turned away from God and he finally sent them into captivity for eight years. It is a near certainty that the period from Joshua 1 to Judges 3 10 was more than 40 years, but I adopted this as a conservative estimate.
No time frame is established from Samson's death in Judges 16 until Eli dies in I Samuel 4, although it appears to have been several years. After Eli's death, Samuel becomes the judge. and continues until Saul is anointed king. Samuel was born during Eli's priesthood, and served until he was an old man according to I Samuel 8:1. Sixty years would seem to be a conservative estimate of the duration of this entire period.
Adding the 40 years for Joshua's influence, and the sixty years for Eli and Samuel, both of which are probably low, and the 160 years additional time listed in Judges to the specified times of other events, and we find that the Exodus or flight from Egypt would have occurred during the period between the Middle Kingdom and the New Kingdom of Egyptian history, around 1550 BC.
Exodus 12:40 tells us that Israel spent 430 years in Egypt, 400 of them as slaves. This places Jacob and his family coming into Egypt during the period between the Old Kingdom and the Middle Kingdom, around 1980 BC.
The Old kingdom collapsed as a result of prolonged drought, a couple hundred years after the Sahara began to turn to desert. Using our estimates, The flood would have occurred about 300 years before the desertification began, or about 100 years before the Old Kingdom began.
According to Genesis 45, Jacob and his family went to Egypt during a drought. There are few records from the period between the Old and Middle kingdoms, and it is not surprising that the coming of a family group of seventy people is not recorded.
During the Old Kingdom period, public works were built by the Egyptians themselves and were usually of Stone. During the Middle Kingdom period, There was a movement to slave labor, and brick became the most common building material. Toward the end of the period, the quality of the brick was much lower, as straw was replaced with stubble as a strengthening material. This is in line with descriptions in Exodus 5.
At the end of the Middle Kingdom, Egypt was conquered by the Hyksos, a weak people from Canaan, who ruled Egypt for about a hundred years. During this period, Egyptian culture largely went underground, and few records have survived. Again, it is not surprising that Israel's flight is not recorded. It is known that most of Egypt's slaves escaped during the period between the Middle and New Kingdoms.
After God brought the plagues on Egypt, the leaders advised Pharaoh that Egypt was destroyed in Exodus 10:7. When Pharaoh released the people, he changed his mind and sent the army to bring them back. Chasing Israel into the middle of the Red Sea, the Egyptian army was destroyed. There were no survivors. It would not have been difficult for even a weak people such as the Hyksos to conquer a destitute and defenseless Egypt.
For almost half of its existence as a state, of all its neighbours Israel has enjoyed its most cordial relations with Egypt, ...