On August 26, 1920, a caravan of Washington officials, automobile enthusiasts, park supporters, and reporters departed Denver for the first stop on the National Park-to-Park Highway, Rocky Mountain National Park.

Nearly three months later, the caravan returned to Denver having completed a 5,000-mile pilgrimage along the longest auto tour route to date, through the twelve national parks of the American West. The roads and automobiles left much to be desired; most roads were not paved. The tour suffered accidents and illness, but grew in numbers along the way as newspapers coast-to-coast covered the trek. By its close, the dedication tour had secured the idea of auto tourism of America's western parks in the national mindset. 


 
The gates of Denver were thrown open yesterday afternoon amid a rousing welcome... to the Park-to-Park trail blazers, to celebrate the completion of the dedication of ‘American’s master highway,’ 5,500 miles long, connecting eleven national marks and unsurpassed for scenic beauty.
— Rocky Mountain News, November 10, 1920