Just returned from a 3100 mile road trip and have to say I am very impressed with my C2 for the complete trip trip I averaged 54 mpg and 58 mph that was for the the number of actual gallons used computer said I averaged 61 with tires @ 40/40 and running the cruise control and air conditioning full time . the car was loaded with me and clothes ,bedding and dog . The car performed better than I had expected after having read some road trip posts road noise was slightly worse than normal due I think to tire pressures being higher other than that I found the car to be comfortable and was not tired or achy when stopping every couple hundred miles ,would consider another long trip with no probem.
G'day, I too find the 'c' enjoyable for long trips, with the occasional short break every couple of hours or so. Frequent fuel stops no longer being available . I think the "road-noise" thing is a consequence of most everything else in the car being quiet. Wind noise at speed is the other thing I hear, when on quieter grades of bitumen. Your mpg (or L/100km here) figures are in line with mine, as I too prefer to use the less-economical cruise control whenever possible (to give my right-leg/ankle a rest) and my passenger wants her cooling/heating comforts, asleep or awake . Only miss the extra cup-holders and junk space from the Yaris/Echo the Prius has replaced. David S.