@ Lordsloth
The Mississippi is thin enough up that way in some places that you could hope over it. The Western line is the actual river, the Eastern is the military lines of defense against the Casualties. Inbetween is a sort of DMZ. I can't decide what to do with that area during the Crash though. Part of me wants to nuke or gas the major population centers as part of the Premptive Genocide policy. It would help buy the government time to establish what is essentially the largest military cordon ever constructed in the nation's history and could be false flagged to justify their nuclear attack on the Canadian cities. However, I also like the ideas of survivors making in that northern wasteland, hiding from both government advance teams mining chokepoints against zombies and the Casualties pouring into the area.
@clockworkjoe
The lemming strategy will work depending on terrain. Just getting them in water won't do anything but disorient them and possibly scatter them with current. They don't drown. But sending a bunch of Casualties off a big cliff might work, or trapping them in a truly epic inferno. However, it only takes one Vector, Aberrant, or unreported bite to royally fuck up that plan. Like we talked about, I'm fine with the floating city ideas and some port city Enclaves so long as California isn't doing just fine or anything that extreme (-ly boring).
@Kamen
Zombies sink and don't have the motor skills to resist a current. They don't drown. I'm also going to note that the fluid the Blight excretes is extremely toxic to insects when consumed and Casualties just want protein from any animal, not just humans. That will answer the question of why fauna and insect-based decomposition doesn't solve everyone's problems in 3 years. So Casualties won't be eaten by fish, but they will break apart in salt water. The Blight relies on the flesh it inhabits to drive around, and salt water has a real bad effect on decomposing bodies. The massive rivers are used because they are deep enough and fast enough to thin out any Casualties going for a swim, and keeping away from the banks makes it that much easier to keep them from even trying. Most get slowly torn apart by the river bottom or wash out to sea, decomposing. Some make it across, justifying the government paranoia and defenses. But it's a manageable number rather than a great horde. Since the Western bank of the Mississippi has been luring zombies into the river's meat grinder for years, rural areas with clear sightlines to both banks are some of the safest areas in the lose because they've been bled out. Cities like St. Louis are still really bad though because buildings block view of the river and the tasty humans from most angles.
As far as tech, Amazon drones are already in the gear list. Monsters that fight for you like Dog are outside the pale (though if you want to train an actual dog to fight for you, I've written some rules for that). I actually want to include some of the advanced prosthetic stuff, but it will not be like Will Smith in I, Robot good. You can take off the governor of force and squash a zombie's head, but you'll risk doing it to items too. Plus, now a body part runs off the Tool rules, meaning you've got limited charges for use in the terms of batteries. So I hope it will be available in the final draft as a character option, but it will be a mechanical trade off. I don't want to write rules yet though because, the more I think about it, I think I need to take another pass on the gear and further simplify it. Just can't figure out how yet without totally abstracting things.