I have a guess at what the "lifeline" will be for state of decay's newest DLC.
Here goes... The "lifeline" is going to be water/commerce/etc between your home base and satellite enclaves. This is exactly what I was asking for when I started speculating on what SOD: Lifeline would be about.
Imagine an open world where you branch out from your home base like a colony of settlers in a new world. Occasionally zombies will attack your home site as well as the satellite enclaves you've settled or joined forces with. If the zombies manage to destroy one of your sites then they can cut off supplies being moved from your home base to your enclaves. You then have a limited amount of time to re-establish a supply route to your neighbors before they start dying of starvation/disease/dehydration.
Having to manage a growing zombie threat (the zombies will also have little strongholds that spread like infestations do currently accompanied by hordes) as well as hold your supply line will be an interesting mix of going on the offensive and defensive. I really enjoy games where one moment you're top dog and the next minute you're running for your life. Hopefully lifeline will be as epic as Undead Labs is making it out to be.
Besides... I could use something new now that Breakdown is a total joke for me. I log in each day to keep my happiness at full for my characters and when I feel I've produced enough items I move on to the next level. Other than experimenting with happiness (for your benefit), there isn't much left for me in the game.
If you'd like help or have questions, please message and friend me on xbox. My username is headache4you.