Similar to your gear ratio post, any OE alternator in any newer pickup (and for the most part older trucks as well) will sufficiently support and "charge" your camper batteries. Although realize the OE charging circuit is very low amp draw/capability.
If you get serious about on the road charging or install or employ a large converter, then greater capacity than some trucks offer may be needed.
If you're just plopping a TC on a truck, virtually all the components are sufficient to haul it save for suspension and tires, depending on the weight of the camper and the truck it's going on.