Cruise control is good to use for those not familiar enough with hypermiling to do it effectively. Why?

Cruse control:
a. Keeps your car at constant speed up hill, which is opposite of driving with load (DWL). It is more efficient to allow your speed to sag while climbing hills. (Reducing the negative effect of gravity)
b. Will keep constant speed downhill. This means when you begin the next uphill segment, you will need to burn extra fuel starting at the base of the hill. It is more efficient to slowly increase speed going downhill (Taking advantage of gravity) so you don't burn so much fuel on the way back up the next hill.

Think of yourself riding a bicycle going up and down hills. You want to keep your effort as light as possible. Do you want to keep the same speed going downhill, and face the next uphill already going at your minimum speed?
Or do you want your downhill speed to increase, helping you up the next hill?

c. Cruise control is boring, compared to planning how to be more efficient for a current segment.
d. It is many, many times more efficient to drive at a slower highway speed. If you set CC for the slower speed you will likely create traffic bottlenecks behind you. Instead you can regulate your speed to slower with light/no traffic behind you, and increase to closer match the group of cars which are approaching you from behind, thus eliminating problems associated with slow drivers.

With that said I've never driven in California and don't know the terrain. If it is a completely flat, level road DWL isn't as effective except for humps such as overpasses.

-Steve

Efficient drivers do it better.
1003 miles a tank personal record. 74MPG calculated. HCH1 CVT