Hmm, well we could try and think of stories fallout related.
There's always the go of the FeV virus experiments, say that before the war there were some government endorsed scientists that promised civilians a good life in a beautiful resort in the snow capped mountains of Alaska (?). However, in an actual fact these people were captured by the government and became the first experiments of the FeV mutation, such data gathered in this place would be one of the founding contributing things that started The Masters army in the first fallout game. Although the data from the experiments have made it through the wasteland, the actual experiments and secret base were lost some time ago. That was when some raiders (which the main character was in) got word of a special bunker with highly advanced weaponry that could be used to sell for lots of caps. They fight to the bunker and eventually open the bunker, however, this only releases a virus and/or genetic experiments that have been left sealed since the beginning of the war, the first FeV experiments. These experimental organism were ruthless and it is up to you, the main character, to save the wasteland and lock this virus and these deadly beasts from the world forever once more.
That setting allows you to get quite creative with weapons and enemies, as it is an experimental lab. You could make extremely disfigured enemies, like humans spliced with spiders and things like that, giving you lots of room for creativity, why still keeping a kind of dark and twisted atmosphere. It also gives you room for super high tech weaponry, as it is a military base, so you could use warp guns, "the original" laser beam and Ion cannons. The setting you have already made could be used when the raiders are going into the bunker or when they are retreating from the bunker after releasing the experiments. The city itself could also have an interesting back story, maybe the civilians were taken from that city? Also, this kind of atmosphere allows for some pretty dark sad imagery, like have notes laying around about people who are just kind of "enjoying a vacation" and then have more notes about scientists "experiments".
For example, On one computer you could have
"Dear Hubby,
This place is amazing! I can't believe they gave us these tickets for such low prices! We are given extremely good food all day, but the owners of this place are really shifty, I dunno, it seems there is something going on. But doesn't matter! I have enough martinis here to not get paranoid, love you xoxo wish you were here!"
Then on a different computer
"Subjects two through twelve experienced severe pain and torture from contagion FeV.0.4
the virus would cause extreme muscle tension, followed by massive neural impulses, causing agony in the subjects.
After about 30 minutes, the subjects started decreasing breathing and eventually died. FeV.0.4 does not work, we need to try more tests."
That's my input anyway