Alright, the last sentence was meant to be a joke, but it is somewhat curious that an 11 day journey took 40 years to complete. Reading the Exodus story, there are many things going on during the travels (and travails, if you will) of this journey.
First, it had to be a logistical nightmare. Attempting to coordinate that many folks without the conveniences of modern communication is a task I would not want to be assigned.
Second, the people kept departing from God's ways. They would be given simple instructions and fail to complete them or totally disobey, or there would be infighting about who should be leading.
One of the ironies of the journey of Exodus is where they traveled. They seemed to be in the Wilderness of Zin (pronounced sin, ironic, no?) pretty often. Isn't that fitting. When we sin, we are lost in the wilderness trying to find our way. We will circle and circle, but never manage to get out on our own. Finally, God has to intervene to pull us out of sin.
I'm glad my journey through the Wilderness of Zin was not a full 40 years, though I have been know to make a left turn headed back in that direction if I am not diligently following the directions provided to me. But God had a purpose for those 40 years for His people, which He tells them:
Deuteronomy 8:2 (KJV)
"And thou shalt remember all the way which the Lord thy God led thee these forty years in the wilderness, to humble thee, and to prove thee, to know what was in thine heart, whether thou wouldest keep his commandments, or no."
While the loops around the desert were to chastise their repeated disobedience (verse 8:5), there were other reasons:
* to humble them-I would image the feeling of overwhelming pride/conceit which could have arisen during the Exodus (immediately after departing anyway): God had just presented miraculous plagues to Egypt and He called you His people; you "borrowed" all kinds of precious metals from the Egyptians, knowing you would never be returning; and, God just crushed the Pharaoh's army under the waves of the Red Sea. Just seems to me that an Air of Superiority could develop.
* to prove them-many issues arose and individual, groups, and an ENTIRE generation were preened from the Children of Israel due to their disobedience, sin, or unbelief. God wanted those faithful followers to enter the Promised Land.
* to know what is in their hearts-in 40 years, people have a great opportunity to come to know God and His law (at the time, they were under the law not stating that we still live under the law), and God could gauge His people by the prolonged exposure to them, whether they would remain faithful and keep His commandments or not.
Number 3, is no dig on the Omnipotence or Omniscience (all powerful or all knowing) nature of God. He knew their heart, but going back to number 2, he was allowing them to prove it. Actions speak louder than words.
Remember, when you feel like you are stuck in a prolonged trial, God has a reason for it. It could be one of the three above. But when you finally stop wandering through the desert, you can enter the Promised Land.