Well, we are back, so I figure I should share our experience.
First, it was great. Maybe a bit too long for the kids. They missed their friends and unlimited data, but oh well.
We ended up changing some plans mid-trip, but we did 5 nights in London, 2 in Berlin, and 7 in Munich.
London was great. Weather was amazing. It was cold, but only sprinkled once or twice. Yes, there were some small issues with holidays, but nothing major. We found a great Christmas lunch and ended up doing a boxing day tour to Windsor/Stonehenge/Bath. It was fast-paced and "big bus", but it allowed us to cram in a lot in a day. Stonehenge was better than I expected.
We had some very memorable experiences. In a pub, we ran into a group from the Queen's guard who participate in the Changing of the Guard. They were really nice folks and we spent some time with them talking and drinking. They invited us to Christmas service at the Guard's chapel to watch them play. They were there in their red uniforms and sounded great. We'll never forget that.
We did a walking tour Christmas even and it was quite nice.
We flew to Berlin on 12/28 (good call on not doing an overnight train) and it just didn't really suit my wife. We did two nights and did a really nice two days of walking tours with someone I found via the forums here. And the Christmas market was superb. But she rebooked us to Munich on 12/30 and we headed out of town early.
The train was easy peasy and really nice.
Munich was fantastic. I could have spent more time there for sure. I think we have some Bavarian in us. People had told us to even skip Munich. Odd. We stayed in the Andaz on LeopoldStrasse. It was really nice, though understaffed. It was a nice stroll to the U-bahn. We spent a lot of time down in the center at the market and shopping areas. I finally got the see the Glockenspiel do it's thing one day.
New Year's Eve in Munich is a sight to see. There are no professional fireworks, but the entire town lights up with people on the streets firing them off. Someone gave my wife a rocket, but it got confiscated by the police heading to Marienplatz (the only place you can't have them).
We did a 3rd Reich walking tour, a city walking tour, Dachau, Salzburg, Neuschwanstein Castle. We ate at some really cool places and met lots of people. I also learned saunas in Germany are more fun when you just relax and go with the flow. :-O
In the end, it's interesting how opinions vary and travel styles vary even with in a family. I learned to just not over plan and expect to wing it a lot. Except for dinners. Reservations are a must.
I think we have decided to spend holidays overseas from now on!
Thanks for all your comments. I hope you each had great holiday experiences. Here's to a great 2020 filled with travel. My next trip is Romania in May. I always love that one.