3 LTR Mazda BT50 Dual Cab.

Dodger
Lots of people use BT50 3lt for towing.
They seem to do a good job.

You didn't say what height wind catching caravan or it's weight. So what you are asking is unclear and replies of others fuel use will be of little use to you until you can narrow it down a fair bit.
Towing 1000kg is somewhat different to 22ft 2.8 ton monster regarding fuel use and ability to perform and go places.
Cheers
Ross M

G'day Dodger,
I'm operating a 2012 BT50 twin cab, auto, with a custom built canopy instead of the tub body. I am towing a 23ft Coromal van, all up weight about 2700kg.

So far I have done 27000ks at an average of 14.7l/100
Towing has totalled 13000km and the consumption averages 15.5l/100,
Driving just as a singleton we are achieving an average of 13.6l/100

So far I am really happy with the vehicle, it is comfortable, has loads of grunt and handles the big van easily even in hilly country.
Recommended purchase

Cheers
Les

Hi Dodger I'm running a 2008 auto SDX dual cab with glass canopy and all up the car payload is around 700kilos including towball download.The van comes in at 2000kilos and is a full van with plenty of height above the car.When towing overdrive is always deselected and travel at 95 to 100kph.On our last trip we travelled from Karumba south to Tasmania where we spent eleven weeks and than back home again.Fuel consumption was around 18-21lp100k.Hope this helps.We will be buying another one when the time comes.