Sports Illustrated: Top 25 Toughest Schedules

Here is the link.

 

Cal is not on the list, but the following opponents are:

 

#1: Washington

#6: Tennessee “Tennessee's difficult season opener at California and its relatively tough matchup with Southern Mississippi compensate for the cakewalks against Arkansas State and Louisiana-Lafayette that make up the rest of the Vols' nonconference schedule.”

#8: USC

#9: Stanford

#20: Washington

#22: Arizona