Join Date: Dec 2011
Location: BOS, BWI, DCA, IAD
Programs: American, Delta, JetBlue, United
Posts: 2,395
A comment on #1. The best-known Christmas market is in Nuernberg, though the one in Munich (which I've been to) is also quite good.
Overall, I'd suggest that you not try to do too much in a short period of time. 25 days may seem like a lot, but you won't want to spend all your time on trains and planes.