how long does it take a dog to acclimate to a new neigborhood?

From personal experience I would have to say it is never safe to just let a dog roam the town. The only way you should let the dog off the leash is in a yard temerarly on a chain. But to answer your question we just recently moved into a new location and withing the same week out dog became quite the escape artist. She would sneak out the back door in the morning, but would always be back by night. It's not as much about getting used to the house as it is getting used to the people. If the dog knows you and is used to you it will come back, but if it is used to someone else then chances are it will try searching for them.