We had an amazing stay at Frantisek's apartment. The location is extremely convenient, all attractions can be reached via walking. The old town square is just 3 mins away. The Charles Bridge is a 10 mins walk maximum. Wenceslas Square is also just a 15-20mins walk.
Frantisek is an excellent host. Shared with us on where to go, and the restaurant he recommended serves one of the best Czech cuisines we had through the entire trip. The street the apartment is on is quiet, beautiful yet very safe. Definitely a hidden gem.