I can't speak directly to your question about the Jeep, but regarding fuel mileage, check the differential gearing in the prospective toad also, as well as engine size.  A vehicle meant to tow more, by torque application, will, as a rule of thumb, get worse mileage than a lighter duty rig with the same engine.  For example, a 3.55 axle ratio (capable of 1 axle turn for every 3.55 engine rotations) should provide better light-duty mileage than a 4.10 axle ratio.  
Many people overlook axle ratio when buying an SUV or truck.  You don't want to get stuck with a high axle-ratioed big engine.  If it's to be your wife's everyday car, rarely if ever used to tow a boat or other trailer, a lower axle ratio with a smaller engine might be best, and most mfrs. offer axle options for any one engine.  If you occasionally like power for passing or backwoods adventures, err on the side of a bigger engine and low axle ratio.
Just my 2 cents,
Joel