My RAM/Lance 650 Adventure(s)

Thanks Jonathon. No, I never considered the 6.4 gasser. I thought that since I was underpowered with the 5.7, that I would swing to the other side and get the most power. At 385 HP and 930 lb/ft of torque, the power is eye popping and really amazing. And I am sensitive to fuel economy, and the Cummins is the best in that respect. Cost of fuel, initial buy-in of the truck, potential maintenance costs don't concern me. I wanted the power, fuel economy, and well, I just love diesels. My last was my Mercedes Benz E-320 CDI turbodiesel, which was the last of the iron block straight six turbo diesels from Mercedes. Amazing engine--power and fuel economy. I miss that current gas E-Class Mercedes is no where as satisfying to drive. There is just something about driving a diesel... So, no, I never considered the 6.4. I think that a 2500 with a Cummins will not have very good payload at all since the engine is so heavy. Need the 3500 if you go diesel and want a TC.
Nice setup! Was the 6.4 Hemi ever a consideration?

We are looking at a 2500 CCSB Tradesman with the 6.4 to eventually put a slide in on. On paper it has a 3600lb payload looks good, I wonder if reality is the Cummins does that much better?
I would look at the sticker on the actual truck you are considering or one as close as you can find it before putting too much stock in the payloads listed on the Ram website. My truck showed up with 400# less than they listed for a 3500 SRW Crew Laramie 4wd Cummins. If you are buying a truck specifically to haul a slide in camper, there is absolutely zero reason to buy a 2500 instead of a 3500. You are literally throwing payload away for no reason.
I thought I would show you what I do when the camper is off the truck. Instead of using a hard shell topper, I use a Softopper. This keeps the weather out of the bed of the truck, but folds like a convertible top (though forward toward the cab) to load large items. It removes easily when using the camper. The rear and the sides roll up too. Nice product. I had one on my Toyota Tacoma too (miss that Taco).

RAM 3500 with Softopper.jpg Taco with Softopper.jpg