My buddy has one.  It's newer than 2004, but the same engine.  It makes good power and pulls a lot.  Towing and hauling aren't about gas mileage- it's all about horsepower and torque.  When you add up the significant extra cost for the diesel engine and higher cost of fuel, it can take a long time for the diesel to pay for itself.  If you're only making a few trips a year, the gas is a good choice.