They missed some of their best possible licks, I think. They talk about the 10 Commandments a lot, for example, but fail to mention that there are three contradictory versions of them.Or the fact that several of the 'plagues of Egypt' were in fact frequent occurences - the Nile turning to 'blood' and being undrinkable is a result of the alluvial sediment that the water pcks up during the flooding season, for example, and the population booms among the insects (and later animals that feed on them, llike frogs) are farily common along any of the large tropical rivers. This would lead one to wonder why they were notable events in the first place, until you find out that there was indeed a large group fleeing Egypt in the wake of the civil war during Ikenaten's time, because the governmental institutions which would normally handle such matters had collapsed, which the chronicles of the time even termed as 'habiru' (which essentially translates as 'refugees', IIRC). It is also plausible that a minor prince or noble name something similar to 'Moses' (which I might add means something like 'royal' in Egyptian, and was probably the equivalent of 'Fitzroy' compare to the name 'Thutmose', which was the name of several pharoahs) would have been their leader, as many of those fleeing at the time were second sons and illegitimates who sided with Ikhnaten in hopes of seizing their elder siblings' holdings (which would relate to the 'killing of the firstborn', perhaps). It isn't hard to imagine them joining together with some of the local Bedouin (who would have been 'wandering the desert' for a good deal longer than forty years), and together turning on the cities of the southern Canaan... but that's speculation.
There are also some parts of the Old Testament - Chronicles and Kings in particular - that are probably fairly accurate records of events, at least as much as any from the time periods in question. For the most part, they record the major events of the era, the succession of the judges and kings of Judea and Yisroel, and so forth, though from the perspective of the current priestly caste, of course. Leviticus, too, is 'accurate', in that it records the liturgical rules and taboos of the
As for Joshua the Magus - I'm surprised they never mentioned that the name 'Jesus' was a third hand translation of 'Yeshua' - most literary analysts agree that the Gospels are a pastiche of several sources, including at least one which had been around since Alexander's time, plus elements of the Elusinian, Orphic and Mithraist mystery religions. While there probably was a man who corresponds to 'Jesus', many of the stories attributed to him almost certainly were older stories re-written, or things which were actually said or done by his followers (or possibly his rivals). I've also found it interesting that the names he gave his followers ('The Rock', 'The Dagger', etc.) are more typical of a revolutionary cell than a religious sect, but that's another argument entirely.