ML Triton DC Auto 3.2L Diesel tray-back, pulling a 2010 Lifestyle Extenda trailer. CT tyres are Mud Terrains, ute tyres are currently factory Bridgestone Dueler H/T's but we're going to D694LT Dueler A/T's later in the year. All gear, with the exception of a big orange Tropical Esky, goes into the CT.
We get between 10.2L/100km on highway & sealed Rds (80-110km/h), and it goes up to 12L and sometimes hits 13L/100km on dirt & unsealed roads. It's gotta be slow-going and hilly for us to go above 13L (i.e Forest Roads, stoney tracks in 4H; and serious hill climbs/range crossings)
I've never taken the CT on sand (i.e. Fraser Is), but the Triton would always suffer when loaded up pre-CT and economy would go up into the high-teens/low-20'sL/100km with the tray-back loaded up. With the CT carrying it all, I'm predicting high-teens on the sand if the tyres are set correctly all-round.
We're pretty chuffed with the economy.. It'll serve us well when we do long around oz style trips.