I don't think Strand knew the apochalypse was coming. I think he's a man who thinks on his feet and has learned to change a situation to his advantage. (Seems like a useful ability/strategy for someone into something illegal.) I think he partnered with Nick because Nick was the best he could do; he had nothing to lose and could be easily controlled. S took the family (if I remember correctly back to S1) because they could get him to where he needed to be. He took the family with him on the boat because he knows that travelling alone is risky and that some of them may come in useful (like for clearing filters of zombie parts).
But I think he also recognizes that there is a balance that has to be kept. He can use people for his own needs because they , too, want to stay alive. But if he threatens a member or pushes too hard (I think Madison is close and Strand recognizes it), he's going to have a mutiny. I think he can sense exactly how far he dare push (cutting the raft free).
Whatever is driving Strand to Mexico is bigger than anything else in his life. I still think it a "someone"; most likely family. What else is worth risking your life for?
I agree with most of this though I don’t think Strand is as smart as he thinks he is. Daniel is completely on to him and Madison is close. Both are close to the end of their tolerance too, it seems. I suspect that the hope of a safe haven at the end of the voyage is the only thing that keeps them from deposing Strand.
No doubt that Strand is an interesting character, more for what we don’t know about him than what we do. The show runner said he was a fixer for the rich and that certainly fits with his opportunistic, unscrupulous, sadistic and possibly sociopathic character.
But he is far from infallible. Strand would never have escaped from the military compound or reached his house and yacht were it not for Nick’s family. His plan fizzled when his driver was eaten and he got himself and Nick locked in a corridor with the undead.
He feels he needs people on the boat for whatever reason but didn’t have a crew lined up, though that could have gone awry. There isn’t enough food on the boat anyway.
He has so far displayed no real survival skills except for the ability to manipulate people. Oh and he can drive the boat but can’t repair it. A high school teacher/amateur mechanic was better able to figure that out.
He is depending on his companions’ decency and observance of old world rules while he breaks them himself: he expects them to obey the laws of property by acknowledging his ownership of the boat and obeying him while he breaks the number one rule by killing people/ letting them die.
It’s hard for me to imagine someone like Strand trying so hard to get to Mexico to reach particular people, but as Vicki says, what else is there of real value in a ZA? Why is there a time crunch? Food, guns, safety etc. are of course invaluable but you don’t necessarily have to go to Baja to get them.