I got a good mixed freeway/highway run in today, about 120 miles round trip. I haven't put any diesel in it yet so I've just been fiddling around with the EVIC numbers, but it showed not quite 22 for the overall trip when I got back to the office which is fantastic even if it is a little optimistic. Commuting from home to work and running errands in the city has been showing in the 16.5-17 range which I'm also happy with if it's at all accurate.
This truck is a fantastic freeway cruiser. It's quiet and tracks great. Even at 80 it just idles along at about 1750.