The problem I'm trying to solve is just a logistics one. In a world with magic, who would a caravan seek out an hire to make the trip easier. As far as petrifying characters, that's an interesting approach and I'll say that's valid.

@enkryptor As long as the source is published by wizards of the coast or in an unearthed arcana article, I'm fine with it.

@KRyan I'm imagining mainly a sand sea type, with the rare dry and rocky areas. There's decent activity from monsters and bandits targeting these caravans, hence the restrictions.