Having spent weeks downloading and installing maps for europe and in particular Croatia, I can report that none of what I can find on the net are sufficiently detailed enough (for Croatia) to be very useful. None of the ones that I tried supported routing. So my conclusions are that most likely Marvin is right when he recommends you should buy one of the available programs that comes with maps.
On the other hand, if you dont want auto routing and are happy to use say nroute (which so far in my experience does most of what I want) then being able to use on-line maps would solve the serious lack of detail available for some countries in Open Source Maps (and others). I have trialled the utilities from (
http://www.allallsoft.com/gmd/) and found them to be pretty good. I can get the detail I want, say for Croatia, from Google maps. These maps are fine for an electronic version of a paper map, however, I cant load them into nroute for simple trip planning and "where am I now" navigation.
I will continue to work on the issue and like Ryanface, I would like to hear from anyone else with any experience in this area