Hey mate, no problem with the input, in fact if I had more time I'd help out more!
Here's a place-by-place of how we followed the route along the Elbe
Setting off
Started in Hamburg at 9:00am and got out of the outskirts by 11:00, followed the river path along the north bank of the Elbe from Geesthact to Boizenburg. We then went through a National park to the North of the river before rejoining the river at Pommau. We wanted to stay in Hitzacker, but there was no ferry so we camped between Alter Haken and the river (first day around 150km).
The forest path in the video
First Camp
Next day we left early and had a huge breakfast at a bakery in lovely Domitz, before following the river closely (if I did it again, I would not hug the river so closely) all the way to Havelburg where we stayed for the night at a campground (urgh), and met the inebriated mayor.
Bridge of a river into Domitz
The mayor and I
The third day was significantly more stressful, trying to make it 120km to Berlin center with only an auto driver's map and no real clue. Got absolutely lost on the ring roads surrounding Berlin and spent all afternoon getting through the outskirts of Berlin (through Spandau)

On the highway into Berlin

Finally!