On future trips, we are considering towing our Jeep Wrangler behind the truck. This will allow us to take the Wrangler on 'real' offroad excursions.
On the upcoming trip to central America, we'll likely just drive the dually with TC. We're not going to be looking for off road excursions just for the fun of being able to drive 4x4. I assume a 4x4 truck (DRW or SRW) should be capable of driving on the (likely few) dirt roads we'll encounter.
The big reason why I wanted a 4x4 truck is because of the chance that it might rain and thus would need 4x4 to drive the dirt roads which are likely in poor condition in those countries.