A Key Event

Well, one of the key events was Ranger going through Search and Rescue training. Without those skills, he would never be able to help the kids from the past. If he couldn't help them, he couldn't get home. The training taught him how to find people in snow, huge crowds, and rain. It taught him how to help people. That's how he managed to save the kids from the books. All that training with Luke and Luke's dad.

Another key event would be-you guessed it- his habits for digging in the garden. He loved to dig in the garden, and it was that habit that made him a time-traveling dog. The worlds first. Also, he just happened to find that box. and then that's when things got a little crazy.