I would think she'd have an ok shot. Europe, and really anywhere, is pretty hairy in summer. The backpacking thing is a plus, though. If you're just traveling through Europe, you should be pretty flexible with your departure/arrival point. If Zurich doesn't work, fly to Milan, etc. It is very good to have that flexibility. As far as coming back, talk to the US Air employee from whom you got the passes, and see how loads are. Pick the city with the most seats/frequency to fly out of. Leave an extra day or 2 just in case, and soak up the adventure of it. Confirmed is for wimps! Nothing like losing all hope, frowning and trying to figure out what to do, and then hearing your name. Literally the last flight I cleared I jumped and made the gate agent in ATL laugh.

Plus, theres nothing like doing a supercheap backpacking trip in the crappiest run down hostels, and then flying back in Business Elite.

We're all happy to assist you should you need anything further.