I'm trying to go to Sofia Bulgaria to trek around eastern europe with a friend for a bit this summer. I'd like to go out May 10th at the very earliest and June 1st at the latest and return before June 30th. I'd prever to depart AVL but CLT and GSP are alright as well. I have 60,000 miles on AA and UA so I can fly Oneworld or StarAlliance airlines. The trick is finding any availability to the trans-atlantic segments. Does anybody have any advice? Thanks

EDIT: Although tempted, I haven't cross-posted this in the StarAlliance forum.