I've thought about the Alps, I've tried to make the map but it's hard to make it look good.
I was thinking that, after a few initial strifes, the few remaining bits of south-eastern France, northern Italy and eastern Austria would join with the surviving southern third of Switzerland to form the Alpine Confederacy, with French, Italian (with strong northern Italian influence) and German (with strong Bavarian and Allemanic influence) as the official languages (maybe minority languages would survive too but they seem in a precarious situation even today).
The resulting community would be stable due to its strong defensive position, but would have a hard time expending and reclaiming back the Silent World areas, due to being surrounded by formely-densely populated areas, lack of many critical ressources (the technological level could well fall back to pre-industrial level in most of the confederacy), lack of many appropriate agricultural land (can't cultivate much in the mountains) lack of good internal travel means within the confederacy, and lack of sea access (the closest point the Alps get to the mediratean coast are currently a very densily populated area lined with many cities).
Since the initial conditions would be pretty bad, I'm guessing the whole area would have no more than 50,000 inhabitants by year 90, though if someone is ready to do a more precise estimate...
I imagine the whole area would develop a new religion which would be a weird mixture of Roman Catholicism and Swiss Protestantism, with many elements from minority religions and folk beliefs taken in as well, with magic mostly of the healing and defensive kind.