Google maps tells me that Joseph and Mary would’ve traveled about 102 miles to get from Nazareth to Bethlehem.
That is, of course, according to modern maps and roads. Mostly dirt, and on a donkey. Probably busy roads, with lots of people. Not really our way of traveling!
Walking at a pretty consistent speed, it would take 35-40 hours. And with the daylight as short as it is during the winter, they probably could’ve only traveled for a maximum of 10 hours.
I’m going to guess it took them 3-4 days to make the trip. Can you IMAGINE three or four DAYS walking in sandals or riding on a donkey??!
So tonight, three days before they ended up sleeping in a stable, might have been the end of their first day of travel. They probably stopped somewhere along the road, in a small town, and had almost as much trouble finding a place to stay. They both would have been exhausted, and still with days left to go. They would have known the Scripture, known the prophecies, and suspected that Mary would give birth. But no preparations could be made, because they were constantly in motion. They had no time to stop, rest, and be ready. The journey had to continue, and they had to press on.