2001 Mazda Protege 1.6 litre 5-speed manual, crank windows, no AC, 14" wheels, about 180K km on the clock at the start of the trip, and likely Mobil 1 10W-30 in the sump.
In August 2012 we drove to the Rockies for a short hiking holiday. Put on about 3500 km and did 40.5 MPG US/48.7 MPG Imperial/5.8 litres/100 km. That was with a slight odometer correction based on official highway 10 km test sections which showed that the odometer was running 1% low.
It's slightly uphill (3700' elevation gain over 1500 km) heading W to Canmore, and there's usually a headwind. We always get better mileage coming home. The speed limit is 110 kph most of the way.