I went to Nationals in Charlotte NC from home back in July, and traveling 77 all the way down I averaged 19.4mpg.
After driving around in a 60/40 mix city highway for 3 days, I was down to 16.9mpg.
Then on my way back home I got back up to 17.6mpg for the whole trip.
That being said, since then the AV has had a mix of roughly 75/25 city/highway and mostly running back and forth from my house to town (2 miles) and back. I am now down to 15.1mpg
I do have a RANGE module that disables the AFM though, so it does cost me a little bit of mileage.
I would say if I reset my fuel milage and did my normal driving for a week, it would range between 13-15 give or take.
I will have to reset it and check it sometime.