Edinburgh can be reached from Germany in just over an hour by plane and offers so many activities for both kids and adults that you could easily stay a few days longer.
The castle can be seen from anywhere in the city. This is helpful, especially for people like me with a poor sense of direction, to find our way back to the hotel in the evenings. Of course, a visit to the castle is a must. There is a lot to see: prison cells, crown jewels, royal living quarters, and much more. From the castle, you have a wonderful view over the city all the way to the nearby North Sea.
Practical tips for imitators ;-):
Getting there: With Ryanair, you can get cheap flights from Germany to Edinburgh if you book in advance. The flight took 1 hour and 15 minutes - Ryanair stated a flight duration of 1 hour 40 minutes.
From the airport, you can reach the city center within 30 minutes by taking the Airlink 100 bus - and can already take your first city tour on the double-decker.
Accommodation: We stayed at the Premier Inn, Lauriston Place 82. The hotel is close to the castle and about a 15-minute walk from the Airlink bus stop - but other bus lines also stop near the hotel. There is a supermarket around the corner, so you can easily stock up on essentials.
If you're not looking for luxury, you'll find an affordable place to stay here. They have family rooms for 2 adults and 2 children - a kettle, tea, and instant coffee are provided in the room. You can add breakfast, and children don't pay for it. In addition to the Scottish breakfast (beans!), there is a continental option, where continental mainly means 'sweet'. You won't find any sausage or cheese here, but you can get by with jam, croissants, yogurt, muesli, and toast for a few days.
Definitely pack: Always have an umbrella with you. Bright sunshine can turn into pouring rain in no time... and vice versa. :-)