As well, I’m uncertain regarding gas or diesel, and srw vs dually. We plan to boondock a fair bit and would like to be able to access off the road type campsites ... but nothing too crazy!
Living in Canada,you definitely need a DRW..You will never find a SRW pickup with enough payload to be legal with the NL 10-2 packed for a long trip.
As for gas vs diesel with a truck camper,a gas does just fine with 4500# in the back..That diesel engine isn't for hauling a measly 4500# it was meant for heavy loads like big fifth wheels etc..JMHO