If you are going to have a payload of over 5,000 lbs. you do not have a choice as has already been mentioned. No free lunch as they say and you will have a much more expensive truck that needs to be special ordered from a dealer and of course a much more expensive camper. In effect you have the equivalent of a Class C motorhome that can be used to pull a 5th-wheel should you choose to do so later (though most people use a SRW truck for that type of use).
The turning radius is something to consider and I would be looking at the Ford F-550 truck versus a GM 3500HD in your situation. The F-550 is built from the ground up to support DRW and not as an add-on option as with the 1-ton pickups.
