This sure is a friendly site.
My truck is a European spec turbo-diesel, "does that make me unclean"
I also get about 300 - 350 miles from about 60 litres of fuel.
I just upgraded my camper and the new one will catch more wind as its seven feet wide, so I will have to really take it easy to get good mileage on the next trip.
We're travelling down thru Holland, Belgium, Luxembourg, Switzerland, Austria, into Italy. 2 weeks for the round trip. Probably doing too much, again.