In August we are planning a trip from California to Missouri and have a choice of two routes Interstate 80 or Interstate 40. I have been both routes and each has their advantages and disadvantages. 80...
We also enjoy the "Loneliest road in America"-- U.S. 50 across NV and part of UT.
But it would really depend on WHERE in CA you are starting. CA is a LONG state and route from San Diego would be quite different than from Crescent City.