LH happily took me from BOS to MUC the night of Thursday November 7th but then couldn't get me to BUD on Friday November 8th. First they rerouted me to PRG, which was subsequently cancelled, then WAW, which was cancelled, and then at about 4pm said "you might get out tomorrow night but we can't promise anything." Since I absolutely had to be in BUD at 10am on Saturday and didn't feel like a 13 hour train ride with 2-3 changes I ended up taking the overnight Flixbus, arriving at 6am Saturday, 18 hours late and a lot the worse for wear.
I still need to apply for my reimbursements. I hear that they're trying to weasel out of EU261 compensation. And I never want to go to Munich again, ever.
The Danube River cruise was awesome, though.