Some points concerning the historicity of the Exodus:
1. The "plagues" occurred in the correct order for natural catastrophes, which are all explicable except for the final plague taking all the first-born of Egypt. However, the phrase "first-born" may have begun as a descriptive term to refer to the young and robustly healthy. In a number of ancient cultures, the firstborn were favored with extra rations and consequently were more likely to enjoy good health. The last "plague" may very well have been the bubonic plague. In our own times, the great influenza epidemic that killed millions of people near the close of World War I tended to kill the young and healthy who hadn't been immunized by exposure to related strains, as had older adults. Still, it is clear that the compiler of the biblical account saw the last plague as payback for the reported murder of Hebrew firstborn boys, a deed done in order to thin the potential military population. Such atrocities are hardly unknown in ancient times.
2. There are Egyptian victory steles referring to the apiru (Hebrews), who were considered outlaws and raiders, and to Israel, a group or groups that at odds with the Egyptian vassal states of Canaan.
3. Moses seemingly spoke Egyptian and needed an interpreter for Hebrew, which he apparently spoke haltingly. Moses is an Egyptian name, as are the names of many of the priestly tribe of Levi. The fact that the Levites had no land and were assigned a priestly role at the shrines suggests to some that the Hebrew tribes already in Canaan reached an accord with the Mosaic band.
4. It seems plausible that an Egyptian leader might have split with the royal family or priestly caste and led a band of converts into Midian, where the moon god Sinai was, some experts say, worshiped. After a nomadic period, this group joined up with other "Hebrews" who worshiped elohim ("the gods"). Later "Elohim" became the generic term for God. Experts agree that the idea that 600,000 people escaped from Egypt is based on a misunderstanding of the development of the Hebrew word for "thousand." The band of refugees would have been in the vicinity of 6,000, it has been argued.
5. Modern research strongly suggests that the bulk of the Hebrews were actually Canaanites who fled oppression in the city-states of Canaan, which were Egyptian vassal states. Thus, these refugees could well claim that they had escaped "from Egypt." The Canaanite states were part of the Egyptian world system. These people lived under severe oppression from the elite who lived in the fortified parts of the cities. But these city-states, along with other civilized areas, fell into decline and disorder (my guess is the cause was desertification of many fertile areas due to unwise farming), and so many "slaves" (and-or serfs) literally headed for the hills. These former slaves gained considerable military prowess, making their hill enclaves somewhat defensible.
6. The story of Joshua's conquest of Canaan may have some truth to it. We now know that every 700 years(?) or so an earthquake-triggered landslide temporarily blocks the Jordan some ways upriver from the Jericho area until it has had time to form a connective channel. So it is possible Joshua and his soldiers crossed the Jordan on "dry" land. As for other accounts in the book, we may agree to a certain amount of poetic license. Very often in Hebrew scripture, the witticisms of the ancient writers come through as obvious metaphors. For example, when Joshua halted the sun, the moon and the stars in their tracks, it seems plausible that the enemy king was defeated in a terrific victory. Kings were wont to take such titles as "The Sun, Moon and Stars." (That suggestion does not deny that God has the power to do strange things with time.)
7. These hill people lived simply, having evidently smashed the idols of their oppressors. But even so, many still worshiped "the gods," kept idols and some imagined that the god Jehovah had a wife. Their houses show a strong sense of egalitarianism, and these people lived for quite some time without a king. Eventually, the incursions of the Philistines (the Vikings of their era) pressured the Israelites to get behind Saul and his chief general David. The name "Jehovah" or "Yahweh" means, it is argued, "He is," which is a form of "I am," or "I am that I am," another appellation for God.
8. Complete monotheism took a long time to take hold among the forefathers of the Jews. For a while, Jehovah (sometimes called Elohim) was referred to as the chief of the council of the gods. I suspect that during the Persian period, some of the stronger ideas of monotheistic Zoroastrianism were incorporated into the "new Judaism," which required a single sect in order to keep peace and in order to satisfy the Persian rulers. The fact that the people of this world "see through a glass darkly" does not for me diminish the power of Jesus, which means "He saves" and "I save." When the cohort come to arrest Jesus arrived, he asked whom they sought. When they replied, "Jesus," he answered: "I am," which caused them to stumble in confusion and darkness.