Hi TC Dude,
With your dually, same as mine, heavy duty adjustable shocks are a benefit. No air bags, not needed. My big TC weighs just under 5000#, and the truck carries it well. Now, mountain driving will be a challange with the 6.0 and the 4 speed tranny. Just stick your foot in it, the engine can take it, and pony up $$ at the next gas pump. I have Happijack front mounts and TorqLift rear mounts and a TorqLift Superhitch. I have a front receiver and often carry the spare there. No problems with overheating. Happy travels.