I think you're confusing it with the EcoBoost engine. The 3.2L Powerstroke only has a single turbo, but that really doesn't matter to this question. Forced induction can minimize the power loss with higher altitude, so it won't lose as much as the 3.7L engine would.
But you're still pulling a heavy RV up a hill with only 180 HP, so it may struggle on some mountain passes. Won't hurt anything though, and you certainly won't be the slowest thing up the hill. The EcoBoost V6 would be considerably more powerful, but it would drink a lot more fuel.
