As you read down through what I have to say, keep in mind that I think the Dodge, as well as the full size trucks have all gotten way too expensive. A truck like I bought in June 04, now costs more than $20,000 than what I paid for ours new. Our wages have not gone up that fast and that I think first model years are a risky venture.
but after all, IT IS YOUR MONEY and all I have to offer is my opinion and experience with our truck.
I have an 04.5 Duramax, so it does not have the improvements that model yr 06 (LBZ, vin code D) brought to the table. I believe my BIO gets around 20 highway with more aggressive treaded tires than I run.
The 06's and later have a 32 bit computer, I have a 16 bit computer, they have a 6 speed auto, mine has a 5 speed. They have different injectors, etc, so what I get MPG wise is not a good comparison.
I have gotten 19.8 hand calculated (by filling up to the neck and seeing the fuel) highway. We also get 12/13 pulling a trailer, but ours is a 30 ft Cruiser that sits kind of high in the air and gets significant air resistance, I can feel it back there. It is harder to pull than the Salem 28BH we used to have and there is only 1000 lbs difference in the base dry weight.
If you follow the link to Edmunds and do some reading on the Ram, there is a comment in there from an owner stating real world mileage.
This is kind of an honest evaluation of the truck
pay attention to what is said about tongue weight.
our world (travel trailers) is different than towing a flat trailer with stuff on it.
Don't get me wrong, I think smaller diesel engines in different sized vehicles is the way to go. Their efficiency over a gas engine is phenomenal.
HOWEVER, what they don't tell you about is the price differential between gas and diesel both in fuel and maintenance It sure appears the market is based on BTUs. Typically here in Ohio where we live, diesel costs more than premium. Plus you have to change fuel filters, I do mine every 5000 to 7000 miles, at a price of $30.00 plus for the primary filter and $25 plus for the secondary. Diesel oil is more expensive, you don't run the same oil as a car does.
Plus you will have DEF fluid to contend with. (actually most if not all new diesel vehicles are running DEF injection for emissions)
Here is talk about that.
Most modern diesels (I would assume the eco one will also) go into limp mode if you forget to add DEF fluid.
These expenses would be there whether you buy a new diesel engined vehicle or used. (just not the DEF fluid, I forget when that feature was added, the 06's/07's do not have it, nor does mine, maybe around 2010'ish)
For our purposes though, towing our trailer would be a bear with a gas engined truck.
Here is a side by side comparison of a new 1500 vs 2500 Rams, both with diesels
Another interesting article, notice down in the text about the price of fuel versus return on investment
You also have to consider where most of your towing will occur. Cross country ? Flat lands -vs- mountains ? I know when I go through the mountains of W. Va and Va, I like the security a heavier duty tow vehicle provides.
Will you outgrow your trailer ? I realize you said you just got it, but like everyone else, you could upsize and then be outside the ratings of the 1500. More camping gear ? I am sure you will get more gear to put in the trailer.
It accumulates fast. Linen, cooking / eating utensils, grills, tools, etc.
Going where you have to haul water in ? All that adds up really quick.
But in the end, the decision will be yours. I just stuck my nose in to help relate what I have learned over the last 10 yrs of towing with a diesel and 25 years of pulling heavy metal gooseneck horse trailers and lighter bumper pull horse trailers.
I have a 1991 454 engined K2500 I am restoring, it got only 7 miles to the gallon towing, our diesel doubles that so I completely understand the concerns about better mileage.