Cycling, Germany and Denmark

My Hungarian friend and I had been planning to do this 650km trip for more than two years. After many excited and over-ambitious ("let's do 200km a day!") Skype sessions we finally made it happen last week. I said my (painful) goodbyes to exchange friends of the past semester, packed up my apartment in Austria, moved across the same floor to my apartment for next semester, and got on the train for 14 hours to Berlin with my 25 euro bike from the police. To be honest, I found the first half of the trip too stressful to fully enjoy it. I hadn't really trained at all and only when we set off did it sink in that we'll have 8 days of full-on cycling ahead of us. We carried a tent, our sleeping bags & mats, cooking gear and clothes as well as food and water on our bikes, which, needless to say, made it a lot more difficult to cycle. My mental low-point was on day 2. We miscalculated the distance to cover that day, and it ended up being more than 120km instead of 80km as planned. That day, my friend's tyre also tore when we were going through a particularly rough, unpaved path in the middle of a forest and had to cycle more than 25km with a broken tyre to the nearest repair shop. The German part of the trip was harder to navigate than expected. The Berlin - Copenhagen cycle route is quite well-known, and follows a much more scenic but indirect way than to simply drive to Rostock, take the ferry then continue on to Copenhagen. This meant that we mostly didn't have to cycle on roads and could go through beautiful forests and countryside, but made sticking on the route another stressful factor. Denmark was an unpleasant surprise in terms of cycling terrain. After the route in Germany was much hillier than expected, we were sure that Denmark would be easy in comparison. The combination of very strong winds and many, small-ish hills meant that the first afternoon when we got off the ferry in Denmark was the most physically challenging part of the whole trip. I definitely enjoyed the second part of the trip more though, I was on a high from making it to Denmark, having completed the first half and being surrounded by such beautiful Scandinavian nature, houses, beaches and people. The Danish people are seriously all so attractive! I liked the routine of being on such a trip; waking up, setting down the tent, always having the same breakfast of muesli, a banana and a big mug of tea , cycling, picnic lunches, arriving at a campsite, cooking big, carb-heavy dinners on our little camping stove, appreciating showers much more and going to bed exhausted before the sun had even fully set. Time and time again on the trip I was surprised at how friendly and helpful strangers can be; on the first night we couldn't find a campsite and someone let us camp on their property, and people would almost always offer help when they saw us, confused and staring at our (inadequate) map of the route.
At the end we spent two days in Copenhagen which I loved, but will write about later since I'm leaving for the Greek islands for a week soon! Please let me know if you have any suggestions for Santorini, Mykonos or Naxos.