[Panther Al]

Sounds like you are off to a good start, your players are clued in to modern games and seem to be open to the idea of a "realistic" game. From horrible personal experience don't drag out the escape from kalisz too long: enough to get them dialed into the mechanics and setting and then kill it the moment it becomes feasible and not one roll later. A prior gm insisted on training players till they "got it" which by the time we all got fed up with no real adventuring was a three months later: he still doesn't get why we all quit.