Originally Posted by The_Breeze
Here's what I do, not that you have to follow.
When I see a small grade, I turn off the CC and use my foot. If she downshifts then, I let her and slow down so she doesn't pop to 4k+. 3 is the max I allow. If you can see the grade coming and you time it right, you can gain speed to help.
It's not a complete cure depending on the grade and it's length but I've achieved 8+ mpg towing a 3500lb towed.
Why turn off the cruise control? Just push the right pedal to speed up and help the cruise control overcome its inability to anticipate the upcoming hill. Take you foot out of it as you crest the hill and let Otto resume control.