ANY electric heater will create a dryer environment because of simple physics. As the temperature of the room rises, the total moisture content remains the same, so relative humidity decreases, making the room feel dryer. An infrared heater has the same effect once the heated objects warm the rest of the room. The only way to increase relative humidity is to add a humidifier. None of the portable infrareds I have looked at have built-in humidifiers, but I have seen larger heaters of both types that include humidifiers and sometimes HEPA air filters as well. Conversely, any heater with a flame will add moisture to a room because moisture is a by-product of combustion. If you want extra moisture, a propane-based catalytic heater is a good choice.
Note that some "infrared" heaters do not actually radiate infrared to the surrounding areas. Instead, the infrared source is internal and it heats an heat exchanger inside the unit. A fan blows air over the heat exchanger which then blows out warm air, heating the room exactly like a ceramic heater.
I'm not clear on the problem you perceive with "collected condensation on the outside". Condensation occurs when a cold surface is exposed to moist air. RV's tend to get a lot of condensation on inner surfaces & windows because they are not well-insulated and thus are cold relative to the air inside. Increasing the relative humidity inside makes the condensation problem worse, not better.
Frankly, I think you (and we) are over-analyzing this. The practical differences are small and depend on particular situations and preferences. If you prefer the infrared type , get one. If you feel a humidifier is a benefit, get one. After a few months of use, let us know how it works out.
