For one, how does a cargo section tend to be laid out? It's usually in the underbelly of the boat, yes? Could someone hide in with the cargo in order to sneak aboard the ship before it set out? If so, just how cramped would such a situation be? And if there's anything else anyone can think of that I should know when writing about two people hiding in the cargo section of a boat, please do tell.
Thanks for your help!