Well I just got back also IB. I was right at 22k after importing some products from Cali :W but mine wasn't as nice as yours. I finally got a gas app on the phone and boy is that DIC off. About 2000 miles total towing and 987 bobtailing. These were my numbers in US gallons .
15.73
9.86
11.3
16.59
17.33
12.87
15.08
14.22
9.95
13.6
Oregon coast highway into the Redwoods and back through Bend. Pretty good passes like Deadmans, Cabbage hill and Lewiston grade. Not sure if rain matters but the 9.95 was a total pull in the rain.