I took the train from Prague to Amsterdam, then the ferry back from Rotterdam, just because it seemed the easiest route. The European overnight trains are a pretty slick operation, with parts of trains leaving and joining in different cities, so the train I was on divided and a section went to Copenhagen, and when it arrived in Amsterdam, a new part had joined from Poland.
The last week I spent in Prague pretty much doing tourist things, including the national museum, which has different parts in several locations, including at the National Monument and the former Parliament building. Both are fascinating buildings. The National Monument comprises rooms to honour the war dead and statesmen, and a chamber for inauguration of the Presidents of the inter-war republic. Communists manipulated the presentation of Czechoslovak history, including choosing to honour the Red Army rather than the resistance. Of course, the monument celebrates a country that no longer exists, so preserving it as a museum makes a lot of sense.
The former Parliament has some interesting elements, including the use of suspension for staircases and even parts of the building. They have a large amount of artworks there too which deserve a bit of attention and explanation.
Prague has the least developed cycling facilities of the cities I passed through, although it also seems that some steps are being taken, and there are a few off road paths, including the main national routes. All of the former GDR towns I went through had very good bike routes and plenty of people using them, just as in other German towns. Although Germany may not have reached Dutch levels of cycling it is very common in Hannover, Magdeburg, Dessau, Wittenburg and Dresden.
The Elbe route (I didn't cycle along it all the time) is quite a mixed bag, the surfaces in the German part include a lot of cobbled roads and paths, and a few ill-maintained dykes. This can slow you down a lot. Other parts had GDR concrete tractor-ways or other surfaces which are a bit better for touring bikes. It is of course very meandering as well, following a river as best as it can.
The whole of the route from Dresden to Prague is pretty flat, I did encounter a few mild climbs but nothing more than a few minutes and nothing very tough. It's really very easy cycling.
On the Czech side, they are putting a lot of money into the route, so long stretches are wide, dedicated tarmac bike paths. Other parts are quiet lanes. Only a few parts seemed difficult to ride on. Cycle tourists from Dresden to Prague are extremely common, and the path can be very busy, often with large groups travelling together. Bars and restaurants target them heavily, and you can find it hard to avoid deciding to stop for a beer.
One thing I would maybe do differently is to take a bit more time over the Elbe journey. There's a lot to see, and I didn't have the time I should have given it. So I might go back! Although, I equally wanted to see more of the Czech Republic and central Europe, like Bratislava and Budapest. But that might take a different kind of trip, starting and ending with a train journey.
Some quick notes on the places I passed through. Many German towns in this area are quite mundane, probably like everywhere, they are somewhat victims to postwar redevelopment as well as the war.
My route is basically avoiding the mountains in the south. After the Netherlands, I headed to Münster, then north east again, keeping to the plains.
Münster was pretty much destroyed in air raids, but has been rebuilt in a sympathetic way, albeit you could accuse it of being a pastiche. It claims to be the cycling centre of Germany, and it certainly does have a lot of cyclists. But so do a lot of other German cities.
I've read a few times that you shouldn't trust people's holiday observations of cycling facilities. I guess that is true, as for instance I haven't done much cycling at rush hour in cities, and of course I've often but not always chosen to use tourist routes like the parts of the Eurovelo tracks.
However, I think you can on a journey like this get a pretty good impression of everyday cycling, just through the fact you see so many towns, junctions, paths and people going about their daily business, as cyclists.
For instance, drivers seem quite aware and generally considerate, and cycling seems to be something a lot of people do for leisure in a way that seems quite alien to anyone used to British day trippers (find a car park, have a picnic not more than half a mile away). I'd often see couples in the seventies out for a day's cycling. Cycle routes and paths so far are have been pretty good, even if not up to Dutch standards, they often come close.
Osnabrück I passed through quickly and headed to my overnight stop in Melle. Between Melle and Hannover, there is a very large ridge, which is broken by the Weser river and a major cycle route alongside it. There were vast numbers of elderly and family cyclists, including one old couple on a tandem pulling their dog in a cart. After the ridge, it's possible to reach a canal and make that your simple and flat route into Hannover.
Hannover was a surprise, arriving in the dark and finding students hanging out in the parks, and passing some very cool looking bars. Hotel Zentrum where I stayed was in the sleazier part of town (it was cheap) but perfectly fine; I went for a quick drink in the nearest bar. In the morning I went to Waschweiber, a café, bar and laundrette. (Does London have one? They are a great idea.) For cycling, it seems really well thought out, with plenty of parks and major bike thoroughfares.
The plan now is to head south towards Prague, via Brunswick, Magdeburg and Dresden.