The GDMBR is The Great Divide Mountain Bike Route that goes from Antelope Wells, NM, at the Mexico Border, to Rooseville, Mt, on the Canadian border. An extended part was added called the Tour Divide that continues to Banff, Alberta. It is a series of secondary highways, back roads, and jeep trails that was mapped out by avid mountain bikers in the early 2000's. It is raced every year from Banff, to Mexico, and was filmed in a documentary called "Race the Divide". There are maps of it, and it passes right through Columbia Falls, MT, where I live. Here is a tracker map I found, along with some details that you might find interesting.