Looking back on the trip a few points come to mind :-
As always we packed too much. The weather in Germany was much hotter than we have ever experienced before and we brought too much cold weather clothing.
Our SQ flights were pretty much all exactly on time and all 4 crews were very good. However, there was some inconsistencies with regards to pre departure drinks and amenity kits. I am not a fan of the SQ Regional J Seats as they are too narrow at my shoulder level and the legroom is not great. The angled bed on the 'long distance' J seats is also not to my liking. The food on the way there was just ok but I guess I picked the wrong options from '"Book the Cook". I made better choices on the way back.
The use of trains was a bit of a mixed bag. They were very crowded for the first part of the trip but then again we saved a lot of money because of the 9 Euro ticket. We had delays up to an hour or so but not as bad as many of the other people we meet had experienced. On the whole I enjoyed the Spanish long distance trains more. But their system is much newer and less busy.
In Frankfurt we spent a lot of time catching up with friends. The city itself is fine but mostly very 'new'. The trips to outlying cities were probably more enjoyable.
Dusseldorf simply didn't take my fancy. It may well have been because of the location of our hotel but who knows.
I would happily recommend Muenster. It is a nice small city and the countryside around is lovely. However, you will have to hire a bike or car to get the best out of you stay. Also look out for music festivals
Berlin is still fascinating and always worth a long visit.
Prague is amazing and we hope to go back and do some of the things we were unable to do.
Regensburg is a fabulously well preserved and interesting town that is well worth a couple of days.
Our time in Munich was tainted by my eye problem. Also we got some wet and grey days which slowed us down a bit.
We were away for around 31 days and I was pretty tired by the end. I had initially planned for around 28 days but it was about $500 cheaper for each of us if we pushed the trip out for a couple more days.