As a further aside to the Ruritanian theme I found this rather spiffing map thanks to the Google elves.
I have no idea who created it ( but thank you) but the use of a slice of the Czech Republic is jolly useful as it gives a good tie in with the description in The Prisoner of Zenda vis-a-vis the geographical distance between Dresden and Strelsau. The regions I am not sure about but the presence( or so it seems) of Grand Duchies or Papal cities or even free cities within the Ruritanian border might prove a treasure trove for justifying local bellicose posturings.
I am still unsure whether to stick with the time frame of mid 1700's as per "The Princess Osra" or the latter half of the 19th as per "The Prisoner of Zenda" and "Rupert of Hentzau"
All to play for...