The National Park-to-Park Highway came to fruition through the efforts of Stephen T. Mather, the first Director of the National Park Service. It was an automobile trail originally designed to connect a few parks, but eventually formed a grand loop through twelve National Parks in eleven western states, a drive of about 6,350 miles.
Even today, this would be a colossal road trip, but the highway was completed in 1920 when roads were mostly dirt and gravel. To plan the roadway, the National Park Service partnered with the American Automobile Association (AAA) and in 1920, a group of twelve men set out on an inaugural trip.
(Anton Westgard, a AAA pathfinder, drove the lead car)
The trip was rather sketchy, adventuresome journey, through often muddy roads and bad conditions, the journey departed from Denver and completed the counter-clockwise loop in 76-days.
The publicity from the 1920 tour, brought many new visitors to the park and seeing America's National Parks by road became a new pastime.