"They look like they are having the time of their lives."If you hike with dogs chances are you have heard sentiments like that from other trail users when they see your happy trail dogs. Dogs are happy on any trail but they become espe- cially excited on new trails. New scents to sniff. New sounds to hear. New sights to see.Every year an estimated 15 million people travel with their dogs. But our best trail companions are not always wel- come where...