James, I agree with you. travel is so subjective. My husband and I always try to end our trips in Croatia., (Zagreb, Dubrovnik and Rijeka) because we have family and friends in each city and we can get in some beach time. so when we begin a trip we pick the furthest point from Zagreb and begin there, filling in cities along the way depending on time.
Jason-Erik, I have been to all of those cities and enjoyed each one for different reasons. I would check the flights and decide based on the best fares/times/airport. I prefer JFK to LaGuardia or Newark and would look for flights from there first. this past summer we did Prague, Cesky Krumlov, Vienna, Bratislava, Budapest, Croatia and had great connections with drivers and bus and hydrofoil. Once you decide your first and last stops, which will be Berlin/Budapest or vice versa because of logistics, you can then build on your vacation. As you do your research, a small town or city might jump out and you decide you must stop there. Especially in Germany, we rented a car and stop at many small towns.