I hear you, but considering the topography we drove through, along with the high speeds on the interstate highways, I figured the mileage was good.

Without the trailer, I run 22 to 24mpg at 120 kph, around 70 mph.
Pulling the trailer down to Virginia and across to Washington on the interstates at 70 to 75mph 120 to 130, hurt my normal mileage a little bit.

Where I thought I would get the best mileage, crossing Canada's prairies, was some of the worse - 11.8 to 12mpg., due I suspect the short hills dropping down to Edmonton, then climbing uphill for almost 3 provinces - long gradual hills up, many miles long, the short little drops into river valleys. IT was strange indeed.

Funny thing is, 130kph was the normal highway speed in Southern Ontario as well, just to keep up with traffic.

In the States, poking along at 120 and being passed by 34 wheel tractor trailers doing 130 to 145 was a little nerve racking at times.

My mileage really sucked climbing up to the continental divide - 12,000 or 13,000 feet at 120 kph.

I really liked the DEF pumps at the fuel stations. In Canada I pay between $10.00 in Southern Ontario to $18.99 in NB and BC. In the states, it was, at the most, $6.00 CDN. per 2 1/2 US gallons, the same container it comes in up here.