Prague Transport for Seniors & Seeking Opinion of a particular Prague hotel

1) you are correct. Public transpo is free for seniors. No ticket required. I was there in 2025.
2) no info, sorry.

regular traveller to Prague here, yes free transport for us older folk (I am now70) carry your passport,not a copy but if you look your age it is unlikely anyone will ask you, i get totally ignored these days by the inspectors.
Mustek metro is close by to the Dominician Hotel, this is an interchage station with both Yellow lines and Green lines metro, you are not a far walk from Narodni Trida ,an other yellow line metro stop and a big tram interchange,so tram up to the castle area can be got from there.
Though the hotel is on a quiet narrow street it is in the heart of the old town so the streets nearby will be very busy with foot traffic., won't be many cars but there will be some.Numerous restaurants ,bars ,cafes etc in the area.

Great location. Three things to note: 1) they have rooms (but not all rooms) with historic features like old fireplaces and wood-beamed painted ceilings etc so ask if you can get one of those. 2) Your breakfast area is in a glass-covered courtyard which is reserved for guests at breakfast but is open to the public for the rest of the day. 3) The top floor is not accessible by elevator so you have to walk the last couple of flights so if stairs are an issue let the hotel know.

Thank you so much fellow travelers. As usual, you have offered very helpful info. Much appreciated!