Based on http://www.csus.edu/faid/financial%20aid%20basics/Cost%20of%20Attendance.html , it looks like the cost of living on campus is about $9,000 more than living with parents and commuting. So probably about $36,000 difference over four years (not $75,000 difference).
http://www.sjsu.edu/faso/Applying/Cost_of_Attendance/ indicates that living at SJSU would be about $11,000 more than commuting to CSUSac, so about $44,000 difference over four years.
Have you checked the net price calculators for both UCs and CSUs?