The Rataje castle would be certainly interesting one. Not only because my friend is a priest in the parish. It is also reasonably close from Sazava, where is the Sazava monastery.
The castle (last time when I was there, cca two or three years ago) is not in exactly good state though. The original keep is still standing, but is not really accessible, and the main building (rebuilt in 17th century in baroque style) although nice is not in exactly good state, it is possible to live there, but there is only one tap of running water in the kitchen and it will be probably quite dusty. Also at the time I was there the castle was lived in by the local priest (who was bit of a recluse and skilled woodcarver), but since then he was relocated and my friend was sent to the Sazava parish, and I think that the castle was not lived in since.
Malesov and/or Prague are ok for me, especially because it means I don’t have to go anywhere far. Actually if the meeting was in Prague, I would be sleeping at home.