I travel to/from BC and Denver quite often (Sierra, 6.2L) sometimes towing a smallish (under 4000 ibs) trailer and sometimes, not. I travel the major highways and, depending on whether the trailer is ...
I have often wished for a three level cruise control. First level, it holds you within a narrow speed, uphill it downshifts, downhill it brakes. Third level, it's like you are cruising on the open highway, uphill it lets the vehicle slow down almost ten percent if it's gradual, downhill it lets you over the save ten percent if it's not sudden. In the middle zone, most of us would just be happy to be there.