Impact on fuel consumption when towing camper trailer

13.5L/100km in the city would be a dream for me!! But it seems about right for highway, a tad on the high side. My last fill, last night, showed 22L/100km in a Jackaroo. I can only guess that your city driving is not typically in stop/start traffic. And I'm going to have to lecture my wife about jabbing the accelerator during the week.

Mike, You don't say what size camper trailer you have. I have a Toyota Prado and a Gumnut camper trailer. The camper trailer weighs 470kg unladen, so by the time, I fill it with water, food, clothes and all the necessary camping paraphinalia that a family of 5 needs etc, its probably around the 680-700 kg mark. On a trip around QLD (11,500 Km) including some off roading and 600 km on Fraser Island, we averaged about 16 l/100km. This is about 1-2l/100 km additional to what I get out of the vehicle normally. I find that trailer tyre pressure and choice of maximum speed can however alter this significantly. So I keep the trailer tyres pumped up to 36 psi, and tend to travel at 95 Km/hr even though highway speed limits may be 110 Km/hr.
Enjoy your travels. Rgds, Mal58

Mike I recently sold my 3l manual Pajero. I used to get 7.5 to 8 kpl around town and 8-9 kpl on the road. Towing a light trailer around 7 kpl and a heavy trailer 6 kpl on the open road. With my roofrack and no trailer on the open road I got around 7 kpl. On the Simpson desert I averaged 6kpl Birdsville to Mt Dare via the rig road and return via the french line. On this trip I had the roof rack and a heavy load but no trailer. You would expect to get worse than these figures with an auto.
I currently have a 3.5 DOHC auto Pajero and get around 0.5 kpl less than the above figures in almost all situations. In my opinion the manual 3l v6 is and excellent vehicle and the consumption on the open road with a/c on but not exceeding a true 100kph is excellent. Go faster and the consumption drops rapidly.