Back when TDL was more active, more than one member wrote a "Saving Susan" story. Susan's shallowness did bar her from being IN NARNIA anymore; but this is not the same thing as her being eternally lost and condemned to the flames below.
Phillip Pullman, the spiteful slanderer who pretended to believe that Mister Lewis was a racist (willfully ignoring the fact that Lewis depicted WHITE Telmarines as bad guys BEFORE he ever depicted any Calormenes as bad guys), claimed that Susan was cruelly barred from the Stable. This also is a lie; Susan still was IN MORTAL EXISTENCE ON EARTH at the time of the Stable Judgment, so the Stable simply was not an issue for her either way. She was no more eternally lost beyond recovery at that point, than the Apostle Peter was eternally lost beyond recovery at the moment he denied Jesus.
The series "His Dark Materials" proves Pullman to be a hater of God; so of course he would want to believe that Aslan would abandon Susan to everlasting perdition.
My idea of a Saving Susan story would take into account her desire to be glamorous; she would be encountered as a woman over thirty, twice divorced and childless. Then, happening upon the place where the travel-rings were buried, she would find two GUINEA PIGS appearing-- the same guinea pigs Digory Kirke left sleeping in the Wood Between the Worlds. They would be able to talk to her, and thus-- even though they themselves never saw Narnia-- would make her unable any longer to delude herself about Aslan being made up.