I got a couple Ideas to toss around
First I will give an example of a short little free online game that is quite close to what you are talking about, its worth checking it out for 20 seconds. The part about it you might want to look at is the random events after each turn.
http://armorgames.com/play/10572/rebuildSecond, I am going to give some possible end conditions if you are looking for some.
1.Have a fully functioning permanent settlement (With this you could work into a time lapse system like the LCS wait system when you pass months by. After your settlement works autonomously for 2-5 years, it could start throwing other random goals at you,
Survive against Large zombie horde (20,000)
Survive against the huge bandit army (2,000)
Rebuild after natural disaster (ex. Hurricane, You could make holes in walls, destroyed buildings, dead people, scattered resources)
Get at least 200 people over to the small island
Get at least 200 people over to the mainland
Get the cure from the outpost 1,000 miles away
Become the #1 city in all of Post Apocalypse mainland America
My questions
1. How big are you thinking, LCS sized squads or like 50 people squads or would it be dynamic sized, because personally I would like nothing more than seeing my squad of 5 people and then 300 turns later or whatever, seeing those same 5 people governing a functioning settlement of 100 people.
2.Would it be just survival, or would it be survive and rebuild.
3. Would this game have 1 release or would you constantly be sending out releases.
MORE TO COME