I have a 2017 Ram 3500 Tradesman with 4wd and 6.7 Cummins Turbo. My fuel tank is I think 32 gals. My guess is when towing, I will have to stop for fuel EVERY day. I could live with every day and a hal...
Yes, have a 110 gal tank. I made it last summer from Anchorage, AK to Coeur d'Alene, Idaho without stopping for fuel. I wasn't towing, but did have 2,000# in the truck bed.
Yes, get a tank. Along with Gas Buddy to avoid the truck stops and states with high fuel taxes, you'll save lots of money.