Skip the 2500, get a 3500. If you're just carrying the TC then a gas engine would be best.
I'm most educated on GM trucks so I'll give you that run down. I'm sure others can tell you about Ram and Ford. A Chevy 3500 SRW comes with s 11.5" AAM rear axle; it doesn't matter if it's gas or diesel, it gets the same axle. A Chevy 2500 gas truck only gets a 10.5" AAM rear axle. If you get a Chevy 2500 diesel then it will have the 11.5" axle. Chevy 3500 trucks also come with wheels that are 1/2" wider than 2500 trucks. This is because they are equipped with larger tires than 2500 trucks.
