I have loved my 2011 Ram 3500 for hauling and towing our camper and toys. Diesel, Crewcab, dually, longbed, etc....55K miles and going great.
Honestly if I was you, I would go test drive all 4 brands: Chevy, GMC, Dodge/Ram and Ford. If you really might upsize your camper I would just be looking at duallies then...usually if you go in test driving new trucks the dealers also have a few newer used ones too.
I would further suggest if you can swing a new truck, pick one you like and do a factory order. That way you get what you want and need and not paying for stuff you don't want.