Touring - Berlin to Copenhagen?

I'm looking to do this route next months, according to this wikipedia article (http://en.wikipedia.org/wiki/Berlin-Copenhagen_Cycle_Route), it's a 630km ride. I'm looking to do it in 3 days on each side of the sea(?) and was wondering if anybody had any practical experience with it, as I have some questions:

1. How even is the terrain? I'm not looking for flatlands, but if it's hilly, then it might be better to budget more days.
2. Where would you recommend I stop for the night (looking for hotels/B&Bs)?
3. Anything I need to look out for/make sure to see/avoid?
4. Any other input or advice would be great.

I've not done this route, but I've toured a lot in Germany. The simple answer is, get the book "Radfernweg Berlin-Kopenhagen" published by Esterbauer. Don't worry if you don't speak German, as the maps are superb, and there will be detailed and extensive listings of all the Uebernachtungsmoeglichkeiten. Sorry, I couldn't resist one of those German compound substantives - it means, "places to stay the night". Hills are marked on the map as either steep or very steep, and there'll probably be an elevation profile for the complete route - ie not too detailed on a mile-by-mile basis, but you'll get a general impression of where the climbs are - if any. The book will also show the "Sehenswuerdigkeiten", ie places worth a visit, both on and (not too far) off the route. But the descriptions will be in German.

I must have about ten of the Esterbauer guides - they're really excellent. If you have three days to spare before the start of your ride, you might consider doing the Berlin Wall cycle path, especially if you're interested in the history of the Cold War. There's an Esterbauer guide for that too.

1. Denmark can/will be hilly, but they are never high hills. They roll nicely along. Are you taking the ferry at Rostock? I don't remember the parts between Berlin and Rostock as to be other than mostly flat, but I didn't travel that region extensively.

2. The only thing I know about this -- since I mostly go camping with a tent -- is that Danish youth hostels are stupidly expensive.

3. The Danes still have their own currency, Danish kroner.

4. ...

EZ way , go east, take the ferry from the Polish port , just across the border.

Never done it, but looked at Berlin to the Baltic, and it looked pretty flat, lots of lakes, wetlands etc. Looked quiet, but nice. I'm thinking of doing it next year, maybe, if I don't go to Spain.