The story is really a masterful creation, but it's cribbed from several good works. For the origin of Moses, we have an earlier King--Sargon of Akkad and Sumeria, I believe.
My mother was a high priestess, my father I knew not. The brothers of my father loved the hills. My city is Azupiranu, which is situated on the banks of the Euphrates. My high priestess mother conceived me, in secret she bore me. She set me in a basket of rushes, with bitumen she sealed my lid. She cast me into the river which rose over me. The river bore me up and carried me to Akki, the drawer of water. Akki, the drawer of water, took me as his son and reared me. Akki, the drawer of water, appointed me as his gardener. While I was a gardener, Ishtar granted me her love, and for four and […] years I exercised kingship
And so on. The adventures of Sinuhe seem to fill in some other good literary holes--and this was a popular Egyptian tale, full of all sorts of good stuff. The david-and-goliath bit is at the end, but the whole legend is very longwinded. Needless to say, he flees his homeland, arrives in a new place, a man of authority (political instead of spiritual) takes him in, gives him lands and flocks to attend to, a wife who bears him children, and so forth. Very similar. He does eventually come home, but only after first whacking a proto-Goliath in a very similar way:
Land gave me to land. I traveled to Byblos; I returned to Qedem. I spent a year and a half there. Then Ammunenshi, the ruler of Upper Retenu, took me to him, saying to me: "You will be happy with me; you will hear the language of Egypt." He said this because he knew my character and had heard of my skill, Egyptians who were with him having borne witness for me.
...
He set me at the head of his children. He married me to his eldest daughter. He let me choose for myself of his land, of the best that was his, on his border with another land. It was a good land called Yaa. Figs were in it and grapes. It had more wine than water. Abundant was its honey, plentiful its oil. All kinds of fruit were on its trees. Barley was there and emmer, and no end of cattle of all kinds. Much also came to me because of the love of me; for he had made me chief of a tribe in the best part of his land. Loaves were made for me daily, and wine as daily fare, cooked meat, roast fowl, as well as desert game. For they snared for me and laid it before me, in addition to the catch of my hounds. Many sweets were made for me, and milk dishes of all kinds.
He came toward me while I waited, having placed myself near him. Every heart burned for me; the women jabbered. All hearts ached for me thinking: "Is there another champion who could fight him?" He raised his battle-axe and shields while his armful of missiles fell toward me. When I had made his weapons attack me, I let his arrows pass me by without effect, one following the other. Then, when he charged me, I shot him, my arrow sticking in his neck. He screamed; he fell on his nose; I slew him with his axe. I raised my war cry over his back, while every Asiatic shouted. I gave praise to Mont, while his people mourned him. The ruler Ammunenshi took me in his arms.
I would say that the translation of the one arrow to the neck to the slingball to the brainpan is a much better and much more visceral one, so whoever wrote a good deal of the Old Testament certainly did some interesting fiction writing to jazz bits up.
As for the rest... I don't know at the moment. There are several accounts of flights, but a flight of slaves seems strange. We do know a few things about that era but it is very confusing, and a lot of it focuses on the Hyksos, a bunch of invaders of partially semetic background and Canaanite names who invade Egypt at some point and bring with them Horses and Chariots. Those are obviously a big deal to Egypt as we remember it now, and Chariots do figure into the exodus accounts. The Hyksos were also expelled at some point, and Egypt was just about two minutemen short of a Border Fence by the later dynasties:
With the chaos at the end of the 19th Dynasty, the first pharaohs of the 20th Dynasty in the Elephantine Stele and the Harris Papyrus re-invigorated an anti-Hyksos stance to strengthen their nativist reaction towards the Asiatic settlers of the north, who may again have been expelled from the country. Setnakht, the founder of the 20th Dynasty, records in a Year 2 stela from Elephantine that he defeated and expelled a large force of Asiatics who had invaded Egypt during the chaos between the end Twosret's reign and the beginning of the 20th dynasty and captured much of their stolen gold and silver booty.
It's really not that much of a stretch to think a bunch of jackholes who invaded, grabbed a bunch of gold and silver shit, might have decided to lay some claim to the land they're squatting in by saying they were slaves who had escaped Egypt after years of brutal torment after being delivered into slavery through no fault of their own. Oh, and the gold and silver... uhhh... the Pharoah gave it to them. Honestly.
So it's a giant mess. Plus, the settlements in the ara don't really show much of a history of moving around. It seems more likely that they were there the whole time--and that periods of aggression and counter-aggression were just generally normal, as various Semite factions battled along the borders of various Egyptian, Hittite, Assyrian forces to carve out a little area of their own. And, from this, you can dervice some kind of a legend. The Greeks were even inspired,
supposidly, by one of these expulsions from Egypt and made it into a Greek 'flight' myth to explain one of the various Hellenic peoples.
Generally, once you've been beaten in combat, you can either write about being kicked off your land, or you can write about travelling from a brutal period of slavery to a promised land. Take your pick as to which would inspire your grumpy Jewish settlers more.
