Interesting post, Fullback..
continued...Ok..now about the Augustan taxation, I don't know what Josephus has to say about it, but I have read a bit of history about Augustus and his taxation work as a consul and, after he defeated Anthony and became emperor, his reform of the taxation system and specifically making all the roman provinces kick in their whack for the running of the empire. Thus Luke's reference to the whole (Roman) world being taxed is fair enough - common knowledge in the Roman world.
But at that time it didn't apply to Judea which was a client kingdom, not a Roman province. That came later after Archelaus was deposed and Qurinus appointed to assess the populace for taxation. While one could say that was a belated application of the Augustan tax, Luke is a bit...glib, in relating the two and of course made it possible for inerrantists to argue that it was a secret tax carried out in Herodian judea.
I'm not sure what your point about travel is intended to show. People journeyed by cart, foot, donkey or horse and Jews visited Jerusalem regularly for festivals at the temple. Travel as such is not the issue - it is traveling to Bethlehem (someone posted that archaeology suggests the place was virtually a ruin at the time) dragging a nine-month - gone wife for no good reason - other than to get Jesus born in Bethlehem.
I can see why Luke thought the census provided the answer but he couldn't have known (nor could Theophilus, probably) that it wouldn't work.