i could dig up my todo list from my never-finished survival project and give you a few things from it
a few i remember are below, i try to explain as much detail as possible
An item you throw on the ground to indicate a location for a helicopter to drop a care package
When thrown on ground, particles will fly up from that position as if it was smoke (like a flair) and a helicopter will
go to it and dropping a care package (well, it will drop a bag or something else that contains the care package)
Will contain ammo, food, and/or armor (depends what tier package drops, based on luck)
Change vaults to houses (and redesign them of course), automatically load everyone into their house instead of Nexus, then remove nexus button
and make it so you go to the front door to leave your house and a UI will prompt asking which location you will want to go to
Danger Zone aka where the zombies are, The Base aka safezone aka Nexus aka a small place where you get prepped to go into Danger Zone such as reloading on ammo, eating to fill your hunger bar, etc, and then The City aka where you can find jobs (interactive activities, like fishing, cooking, and whatnot) to earn gold which can buy supplies such as food, weapons, and more, even upgrades such as fancier house, larger hunger bar, etc.
The City doesn't have zombies in it, but the zombie outbreak caused people to go crazy so watch out for muggers (they will be like candy gnomes just look different, rare sighting, they run somewhat fast, they will just run on top of you and X gold will be stolen from your balance and you will have to kill them and a bag with whatever amount they stole from you will drop, it will be a public bag though so if you see a random mugger running around you can kill it and it might have someone elses gold drop), and also watch out for the homeless, they will always beg for gold when you walk too close near them, but you never know, they might have something in return.
Skills Management - You will have certain skills (the level these skills are it are kept in database so they save properly and update easily) such as Shooting (visit shooting range, or just have good accuracy in general to level up in this Skill), Bravery (spend most of your time in the Danger Zone), Charm (donate a lot, help people out, etc), and more that I am still thinking of:P