The apartment is a great location, the train station (via PID is only 12 minutes) and city center (via PID is 8-10 mins or 20 on foot) was near. Julius and his wife were very helpful, they provided us with instructions and also were waiting, because we were a bit late due to complication in traffic. The place was just as advertised, and completely fulfilled our needs. They were also books and maps about Prague in many languages, so planning was easier, even tough there is also a good internet connection for online planning.
Overall, very satisfied