This coming from my username......DO NOT get the Eco diesel! in fact I would skip any small diesel. just too many issues with them that make them unreliable for a vacation vehicle.
Stick with a good reliable V8. I know you can get a 35 gallon tank in a Hemi. also the Eco Diesel can only be had with the small tank in the quad cab because the Def tank takes up the space of the larger fuel tank. you would have to get the crew cab for the larger tank.
As for going with a larger fuel tank, as long as one is made for the truck and the fit is perfect that can be a good way to go!
EDIT.....I see the OP ordered an EcoDiesel. Hopefully he gets a good one and has no issues. I wish him luck, he will need it.
