“In midwinter [1858-59] Simpson requested the Secretary of War, through the Bureau in Washington, to authorize a program of exploration for the spring which included a wagon-road survey from Camp Floyd to California by way of Carson Lake, to be followed by a an eastern trip to seek a shorter, better route from Camp Floyd to Fort Leavenworth . . . Secretary Floyd approved the project, and through General Johnson gave Simpson a carte blanche to organize the expedition. . . .
At Camp Floyd [after the exploration], Captain Simpson dispatched Lieutenant Kirby Smith with a small detachment to return over the last 100 miles of the route to straighten sections and mark them with stakes and guide posts. Wooden troughs were to be built at the springs in the desert to collect and save the water. . . .
Several days after Simpson’s return, California emigrants started west over the new route. One party with seven wagons and another with thirty were supplied with an itinerary. The same information was given to Russell, Majors & Waddell who planned to drive a thousand head of cattle over the road to California. . . .
The Pony Express, which began running between San Francisco and Salt Lake City in April 1860, used [Simpson’s] northern [outbound] route over the 300-mile course between Genoa and Hastings’ Pass, and after continuing along the 175 miles of Chorpenning’s extension of Simpson’s route as far as Short Cut Pass, it traveled along [Simpson’s] road to Camp Floyd on the way to the Mormon capital. . . .
According to General Johnson, emigrants passed daily over the new route to California, many driving large herds of stock, so that in a single season the road was well marked.