Not all roads were gravel in the "old days." Most of US 40 was paved to Salt Lake City by WWII, much of 550 between Durango and Grand Junction was paved by the end of the same war, with the portion between Coal Bank and Molas Pass getting paved at last about 1957. All the roads our family took during the war years to Evergreen outside of Denver were paved, etc. Our first trip from Denver east to Washington, DC in 1946 was all on paved roads, though there were miles of brick paved roads in Missouri. Many of the roads in RGS territory were paved during the war as part of the Uranium mining efforts for the Bomb, and that's all well documented. And for the most part, gravel roads of the 30s and 40s were all pretty well maintained.