I can't speak for the efficiency in method of delivery back in the 1930s but I can tell you that the RPO markings are:
Canandaigua (NY) & Williamsport (PA) RPO; and
Buffalo (NY) & New York (NY) RPO
The distance today between Geneva, NY and Leicester, NY is 55.4 miles (via main highways that weren't in existence back in the 1930s).
According to this historical piece,
"a dozen trains left Canandaigua on the two New York Central Lines that converged (t)here." which could document the reason why the Buffalo & NY RPO was involved in the transportation of this piece of mail:

