If it's just narrative, the player could take his sweet time walking around without doing anything to find the cure for it. I suggest a timer to find the cure, just like Fallout 1 did to find another water chip.
Example:
The player has 150 days to find a cure, and every 25 days, he loses 5% of...
I saw on the thread something that bothered me a bit, and it's about the Institute and Big MT:
"thanks to a partnership with the Big MT and the sharing of low orbit satellites".
Instead of that, the institute could have a "fight" with Big Mountain and then eventually hijack their satellite (You...