Let me expound a little further:

I'm liking kureneko's suggestion of the classic Prague/Vienna/Budapest triangle. I can personally recommend the Budapest Castle Hilton. Very nice hotel, they treat elites right, fabulous lounge, lots to see right in the neighborhood, etc. No experience with the other cities (yet!) but a search will turn up lots of good scoop.

I believe you can take a Danube cruise to get between Budapest and Vienna. It would probably be quite comfortable and absolutely gorgeous scenery in the late Fall.

At least two LCC's (Wizzair and Skyeurope) fly in/out of both Vienna and Budapest (not sure about Prague) and they would make it easy and cheap to get there and back to a gateway.

Finally, I think you ought to re-think the GLONP aspect. Two GLONP's will set you back 350,000 points and give you six nights in each of two locations. Six nights might be a little much for those cities. Whereas three AXONs would cost a little more (3 X 125,000 - 375,000), you get three cities with 4 nights each, and 4 nights is just about right for these places.

Of course, if you're off to the Indian Ocean, pay no attention to all this.