I want to upgrade to a diesel for towing our travel trailer. Need real world fuel economy numbers?

I am considering buying a diesel to tow our trailer. Can anyone tell me what they are getting for mileage out of 06-07 cummins (5.9 OR 6.7) Powerstroke (6.4 or 6.0) or Duramax 6.6. Would love to know what you get solo AND towing (and how much you tow) Are your numbers with or without a programmer like bullydog ... THANKS!

With the price of diesel fuel going up much faster than gas, you might want to wait on converting.

Unless you have a way of making your own biodiesel.

i'd think twice about that, they're really gouging people on diesel fuel right now, the diesel will get better fuel mileage but it'll still cost more thanks to the oil robber barons, but if you still want to, the duramax gets the best fuel mileage of all those, and it has the most power, GM makes a good product,

The newest Duramax is rated for the most power, but it's only by a measly 5 or 10 horsepower, and 5 or 10lb-ft of torque....those ratings are at the crank. The numbers that matter are the ones that make it to the ground.
The Duramax and Cummins get better mileage overall than any Powerstroke, and are both much more reliable than the 6.0 and 6.4 Powerstroke. The Cummins has the most outstanding reputation out of them all in just about every category.
The I-6 Cummins is a true puller, making it's torque lower the rpm band. The only potential drawback to it I think is the narrow rpm band. Cummins engines have lasted much longer and been more reliable overall than the V8 diesels.