We are now at 5 months on the road with the Ram 3500 4x4 crew DRW pulling a 39 ft. 2013 Montana. We pulled a heavier Mobile Suite for 8 years small distances with a 2500 short box 2500 Chev. Ext. Cab. Now we know that was dangerous even at 65 miles from home!
The difference in your plan with 3500's will mainly be parking those hips in city areas and close lanes when you are un-hooked. We have done Tucson, Dallas, Eugene, Or., Seattle and Portland areas and did OK but some planning is required sometimes. The long box dually means longer walks at the supermarket!! but for the stability and weight of 5er I think we made the best decision.