Hell, the Acadia only gets 23mpg highway. Last time I towed to Deals Gap with my truck I was getting around 10 with only 2 bikes. Last fall I towed a bigger trailer and 3 bikes, got 5.
You find a truck or SUV that can get 30 mpg, let me know. And I'm not talking about the little Honda SUV's that cant tow itself out of a wet paper bag.