After Joseph's visit from the angel and his acceptance that Mary was pregnant with the Son of God, he found out that there was a census being taken and that he needed to return to Bethlehem with his wife to be counted for the census. This census was ordered by Cesar Augustus for taxation purposes. This would of been a very long journey from Nazareth to Bethlehem. Mary being pregnant would only make this trip harder.
When you take in all the factors that would be involved in this trip, it is amazing that they even made it to Bethlehem. We believe that Mary rope on a donkey while Joseph walked leading them along the road. The road would of been bumpy and hard on the pair as they traveled. It would of not been easy for Mary if she hadn't been pregnant but she was and who knows what it would of been like.
I have taken plenty of long youth trips with the girls of youth group and one thing that takes place on all those trips are bathroom breaks. OK, I have to take them for myself too, but again with the pregnancy I am sure that they made more than one stop along the way. On top of that you might have had morning sickness or even motion sickness. They would have had to stop for that as well.
When a women is pregnant they have a tendency to have weird food cravings that make them want certain foods in combinations that you might never heard of. Joseph may have been made to stop to find some foods that he may never thought he would of had to find. This would again tack on time to their journey.
Although I joke about all of these things that might of happened, it is true that this journey to Bethlehem was tretrious and without Enterprise rent a car or Southwest, who doesn't charge bag fees for the baby bag they had to carry, it was a hard, long walk.
But Joesph was able to lead them to Bethlehem safe and sound. Unfortunately he forgot to make his reservations through Priceline or Expedia so they didn't have a room when they arrived. They had to find a place quickly because it was nearly time to Mary to give birth. What would they do?