Sorry but this is the only picture I have right now which shows the camper related to the tank. Plus, I obviously don't have a Ram. But I suspect we're very similar in specs for the bed size.
As I said, I used to have the 91 gallon RDS which was bed high. It was pretty much level with the top of the bed. But going to this higher tank saved me about a half foot of bed space. Either one will work but I like this taller one better.
Eight trips and 3184 miles later, it has never come close.
By the way. To get the full 91 gallons in there, you'd have to stand there and let it trickle in forever because the foam. But I can get in the upper 80s on gallons in there plus the full 35 gallons or so in the stock tank. 120+ gallons of fuel can go a long ways. Yes, I have to stop to pee from time to time. But I can pee wherever I want to and not base it on a fuel stop if I don't feel like it. I'd rather pee at Chik-Fil-A and get a snack while I'm there.
If I can help it, I will always have an auxiliary tank in the bed. Plus, the tool box holds quite a bit: full socket set plus other tools, the caps for the holes in my bed from the hitch, shop rags, PM-22, plus some spray lubricants.
